With programming language from scratch lessons. Is English Important

• Technologies: HTML, CSS, JavaScript, Git, Node.js, React.js and more.
• English language.

The freeCodeCamp program consistently teaches the user all the basic aspects of web programming from basic concepts to advanced development techniques. At the beginning of each lesson, you read the theory, then put it into practice: write code in a special editor, and the system checks you. If difficulties arise, you can discuss them with other students on the forum.

At the end of the theoretical modules, you are shown projects on the basis of which you should create your own web applications. The results of the development must be published on the resource, after which they can be evaluated by other users.

In addition, freeCodeCamp helps students get into teams and work together on real non-commercial projects. This is a good chance to get valuable development experience and portfolio needed for employment.

2. Codecademy

• Technologies: HTML, CSS, JavaScript, Angular.js, React.js, Python, Ruby and more.
• Cost: Free or from $20 per month for additional content.
• English language.
• Difficulty level: easy-intermediate levels.

Like the previous resource, Codecademy focuses on teaching web programming. You read the theory, and then complete tasks in an interactive code editor. It offers the user separate courses dedicated to different technologies. The main part of each of them is available for free, but verification tests and project development tasks open after subscription.

Codecademy also has comprehensive paid programs that organize and combine materials from different courses. For example, the Build Websites from Scratch program teaches you step by step how to build a simple website from scratch using various technologies.

3. Coursera

• Technologies: HTML, CSS, JavaScript, Angular.js, Java, Python, Ruby, Swift and more.
• Cost: Free or from $49 per month for additional content.
• Language: English, Russian and others.
• Difficulty level: all levels.

On Coursera you will find many courses in different programming languages ​​from the world's leading universities. Here you can learn not only web development, but also the creation of mobile and desktop programs. Some courses are self-contained, but most are grouped into specializations - sets of related courses.

You can view the theoretical material presented by texts and videos for free. But most of the test and practical tasks that require verification by a teacher or other users are available only for a paid subscription.

4.edX

• Technologies: HTML, CSS, JavaScript, Java, Python, Ruby and others.
• Cost: Free or from $49 per month for a certificate.
• Language: English and others.
• Difficulty level: all levels.

On edX, you can access courses from renowned companies and universities. Among them is, for example, the famous introductory course for novice programmers Introduction to Computer Science from Harvard University. Educational content is mainly represented by video lectures and texts. Some courses contain quizzes and other interactive activities.

For the passage of most materials, the platform does not ask for money. But you can get a certificate confirming the successful completion of a particular course only for money.

5. INTUIT

• Technologies: HTML, CSS, JavaScript, algorithms and databases, C#, Java, Python, Ruby, and others.
• Cost: free of charge or from 500 rubles per month for the services of a tutor.
• Russian language.
• Difficulty level: all levels.

The INTUIT educational platform catalog contains text and video courses from Russian educational institutions and international IT companies. The content of the site covers all major areas of programming from website development to the creation of desktop programs. Self-study is free, but there is a paid service in which the user is assisted by a personal tutor.

6.Stepic

• Technologies: JavaScript, C#, neural networks, C++ and others.
• Cost: completely free.
• Language: Russian, English.
• Difficulty level: easy-medium.

Another non-profit platform, courses for which are created by Russian companies and universities. Although there is not much material on specific programming languages ​​on Stepic, here you can learn fundamental knowledge from the field of mathematics and the theory of algorithms that will be useful to every developer.

7. Modern Javascript Tutorial

• Technologies: JavaScript and others.
• Cost: free of charge or from 6,500 rubles for an additional course.
• Russian language.
• Difficulty level: all levels.

This resource is dedicated to the JavaScript language and related web technologies. Here you will find a very detailed, well structured and easy to understand text course on JS. Tasks after each topic will help to consolidate the acquired knowledge. At the same time, the material is purely theoretical and does not teach how to create projects in practice.

You can study the textbook for free on your own or pay for advanced courses that include learning JavaScript itself or related technologies with a teacher.

1. Self

If you have an iron will and a burning desire to become a programmer, you can achieve your goal through self-education. This is not the easiest and shortest path: you yourself will have to deal with informational chaos and fight procrastination. But you can study at a convenient time for relatively little money or for free.

The easiest way to start is with interactive online courses. There are many on the Web whose materials explain the basics of programming in an accessible way and set the direction for further development. Pay special attention to those courses that teach on examples of real projects, that is, they tell you step by step how to create a specific program or website.

Platform with free web development courses freeCodeCamp

Remember that you won't succeed without practice. Learn from project-oriented courses and try to write programs and websites that are analyzed in them. Look for lectures on YouTube with a breakdown of projects that you would like to develop. First, copy other people's work and analyze it. Then try to deviate from the original, experiment, change individual elements until you can create something unique.

In addition to courses and video lectures, there are official documentation available on language sites, and. When you understand the basics, look for recent publications with the subtitle Best Practices for your chosen programming language. These books contain the best development techniques.

Be sure to set a goal to create your project and constantly work on it.

This will help to consolidate the acquired knowledge and understand what information you still lack. Your skills will develop along with the project. When you finish it, work on a new one - more difficult.

If you have any difficulties in the learning or development process, you can always turn to programming communities like "Toaster" and Stack Overflow for any question. For example, they will help you solve a problem, choose a good course, or point out errors in the code.

Service of questions and answers on technological topics "Toaster"

It is convenient to hone your skills at special sites where you can compete with other programmers, solving various practical problems using code. These services include Codewars, TopCoder and HackerRank.

If you feel that your development has reached a dead end, or you want to speed up your learning, try the following options.

2. With the help of a mentor

A mentor is a personal mentor who points out mistakes, warns about pitfalls, and helps to plot a course of study. A good recommendation at the right time can save you a lot of trouble and save you a lot of time. Therefore, the mentor will not hurt anyone.

Find out if there are developers among your acquaintances. Perhaps one of them would like to help you. If you do not know such people, you can look for them in the programming communities. For example, on the same "Toaster". Only mentoring services are not cheap, but no one wants to spend a lot of time on strangers for nothing.

3. Teachers of "live" courses

Distance and face-to-face courses with teachers who teach programmers from scratch have become incredibly popular in recent years. As part of this format, you also have to work a lot on your own. But you will be engaged in a professionally prepared program, and a living person will check the solutions to problems. The disadvantages of the courses include the high cost of education.

Popular Russian-language online platforms that provide system training for programmers: Netology, GeekBrains and Loftschool.

If you prefer to study in person, you can look for educational centers that teach programming in your locality. Unfortunately, such establishments are most often present only in large cities. An example is the STEP computer academy, which has branches in several countries.

4. At the university

If you have a lot of time left and you are sure that you want to connect your life with programming, you can study computer science at the university. But keep in mind that traditional educational institutions are lagging behind progress, so you will have to master modern programming languages ​​and other technologies on your own.

On the other hand, the university will provide fundamental knowledge of mathematics, algorithms and other areas that will help you become a high-class programmer. Over the years of hard study, you will form the right type of thinking, thanks to which you will grasp everything on the fly in the professional field.

How to choose a direction and language

There are several areas in the IT industry, each of which uses its own set of languages. We list the main areas in order of increasing complexity:

1. Web development. Popular languages: JavaScript, PHP, Python, Ruby.
2. Mobile development. Popular languages: Java, Swift.
3. Development of games and programs for desktop computers. Popular languages: C++, C#, C.
4. Big Data, machine learning. Popular languages: Python, R, Scala.

What to look for when choosing

To make the right choice of direction and, in particular, the language, consider the following factors: the complexity of mastering and the number of training materials on the Web, your personal preferences (what exactly do you want to develop) and the demand for the language in the labor market.

Graph of demand for languages ​​in the international labor market / research.hackerrank.com

The demand for the language in your area is easy to check on job search sites. Just open the section for software developers and see the number of available vacancies.

If you can't decide

If you're confused, take a look at JavaScript, the language in which almost the entire web is written. Many organizations and programmers advise beginners to choose this particular language as their first language.

For example, the founder of the educational resource freeCodeCamp Quincy Larson JavaScript to all beginners. Larson makes a very simple argument:

1. JavaScript is relatively easy to learn. And to write something and run it in this language, it is enough to have a code editor and a browser.
2. JavaScript is the most demanded language in the international labor market and it has great prospects. Large companies like Google, Microsoft and Facebook are investing in the JavaScript ecosystem.
3. JavaScript has a very wide scope: from websites and browser games to mobile applications.

In addition, a large developer community has formed around this language. The high interest in JavaScript provides a huge number of courses, books and other educational content.

What else should a programmer know: mathematics and English?

Any programmer needs a deep understanding of . For areas such as game graphics development or big data, a mathematical mind is a must. But when it comes to web development and the creation of simple programs, in most cases, mathematics can be dispensed with. Although there is no consensus among professionals on this matter.

But understanding English, at least at the level of fluent reading of the documentation, is mandatory for all programmers. Official documents and most educational materials appear primarily in English. are often out of date before the translation is released. In addition, knowledge of English opens up prospects for working with the whole world.

How to get your first experience and first job

To find your first job as a programmer, you must have a portfolio. This is a project you created, or rather several, that demonstrate all your developer skills. The program of most courses includes the development of projects that can be included in your portfolio.

A very valuable item in the resume will be the presence of work experience, especially team development. But where to get it if you are looking for your first job?

1. Complete multiple orders for . It can be Freelance or Upwork. Offer your services for free, then the first customers will come to you.
2. Find like-minded people and create a common project with them. People unite for such purposes in almost every educational platform where there are programming courses.
3. Choose courses whose organizer helps with employment. For example, at GeekBrains, after training, access to internships from different companies, including paid ones, is opened. GeekUniversity and STEP guarantee employment for their graduates.

Before you do not forget to search the Web for lists of tasks and questions that are often asked to job seekers.

C Programming For Beginners - Master the C Language

Duration 22:23:08

C Programming For Beginners - Master the C Language - Full list of lessons

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• Lesson 1 00:12:23
• Lesson 2 00:05:54
• Lesson 3 00:17:54
• Lesson 4 00:13:41
• Lesson 5 00:12:10
• Lesson 6 00:16:28
• Lesson 7 00:06:48
• Lesson 8 00:11:22
• Lesson 9 00:05:11
• Lesson 10 00:08:03
• Lesson 11. (Challenge) Writing a C program that displays your name 00:05:15
• Lesson 12 00:04:17
• Lesson 13 00:07:00
• Lesson 14 00:12:32
• Lesson 15 00:05:01
• Lesson 16 00:12:12
• Lesson 17 00:04:13
• Lesson 18 00:13:15
• Lesson 19 00:16:56
• Lesson 20 00:17:57
• Lesson 21 00:19:24
• Lesson 22 00:13:45
• Lesson 23 00:11:17
• Lesson 24. (Challenge) Print the Area of ​​a Rectangle 00:07:12
• Lesson 25 00:12:14
• Lesson 26 00:03:35
• Lesson 27 00:08:53
• Lesson 28 00:08:39
• Lesson 29 00:19:56
• Lesson 30 00:18:42
• Lesson 31 00:12:44
• Lesson 32 00:09:59
• Lesson 33 00:03:52
• Lesson 34 00:11:12
• Lesson 35. (Challenge) Print the byte size of the basic data types 00:03:06
• Lesson 36 00:05:39
• Lesson 37 00:08:40
• Lesson 38 00:21:33
• Lesson 39 00:15:45
• Lesson 40 00:05:00
• Lesson 41 00:18:18
• Lesson 42 00:17:50
• Lesson 43 00:13:05
• Lesson 44 00:11:03
• Lesson 45 00:07:24
• Lesson 46 00:17:49
• Lesson 47 00:18:37
• Lesson 48 00:10:10
• Lesson 49 00:12:45
• Lesson 50 00:04:25
• Lesson 51 00:06:22
• Lesson 52 00:12:34
• Lesson 53 00:05:43
• Lesson 54 00:14:35
• Lesson 55 00:13:43
• Lesson 56 00:14:59
• Lesson 57 00:10:41
• Lesson 58 00:13:18
• Lesson 59 00:10:12
• Lesson 60 00:04:50
• Lesson 61 00:21:09
• Lesson 62 00:06:46
• Lesson 63 00:24:07
• Lesson 64 00:08:11
• Lesson 65 00:14:39
• Lesson 66 00:07:42
• Lesson 67 00:20:31
• Lesson 68 00:20:08
• Lesson 69 00:07:06
• Lesson 70 00:03:33
• Lesson 71 00:15:28
• Lesson 72 00:02:13
• Lesson 73 00:16:47
• Lesson 74 00:21:22
• Lesson 75 00:06:14
• Lesson 76 00:12:42
• Lesson 77 00:13:54
• Lesson 78 00:11:32
• Lesson 79 00:11:22
• Lesson 80 00:07:46
• Lesson 81 00:13:02
• Lesson 82 00:20:15
• Lesson 83 00:07:31
• Lesson 84 00:03:20
• Lesson 85 00:07:21
• Lesson 86 00:17:44
• Lesson 87 00:07:27
• Lesson 88 00:08:51
• Lesson 89 00:14:55
• Lesson 90 00:07:47
• Lesson 91 00:17:45
• Lesson 92 00:02:37
• Lesson 93 00:07:15
• Lesson 94 00:02:15
• Lesson 95 00:07:42
• Lesson 96 00:03:50
• Lesson 97 00:09:31
• Lesson 98 00:02:55
• Lesson 99 00:10:48
• Lesson 100 00:20:01
• Lesson 101 00:11:19
• Lesson 102 00:10:05
• Lesson 103 00:20:48
• Lesson 104 00:11:28
• Lesson 105 00:02:05
• Lesson 106 00:08:37
• Lesson 107 00:03:24
• Lesson 108 00:13:48
• Lesson 109 00:10:27
• Lesson 110 00:16:21
• Lesson 111 00:14:51
• Lesson 112 00:09:36
• Lesson 113 00:11:31
• Lesson 114 00:02:22
• Lesson 115 00:07:40
• Lesson 116 00:03:24
• Lesson 117 00:10:30
• Lesson 118 00:02:24
• Lesson 119 00:07:22
• Lesson 120 00:03:48
• Lesson 121 00:12:11
• Lesson 122 00:03:22
• Lesson 123 00:07:33
• Lesson 124 00:09:41
• Lesson 125 00:13:36
• Lesson 126 00:00:49

C (si) Programming will increase career opportunities. Become a better developer in other languages ​​by learning C.

You have never programmed before and thought or said that C is a good programming language to start with. Truly said!

Perhaps you have experience with other programming languages, but want to learn C(C). This is a great language to add to your resume!

Or maybe you're stuck in a low-paying job and want to move up to a better, more senior position. Learning C (C) can help you!

The point is that learning to program in C is not only a great programming language, it will help you improve your programming in other computer languages!

Why learn C?

C (C) is often considered the mother of all languages ​​because many other languages ​​are based on it.

C (C) is one of the most powerful languages ​​ever created. Given that it was created over 40 years ago, it is still heavily used and is usually in the top 5 or 10 most popular and most widely used programming languages ​​in the world.

Learning C(C) can teach you how to program better in other languages ​​like C++, Java, or C# by equipping you with a mental model of what the computer is actually doing when you run your programs.

By learning how things really work "under the hood" and understanding memory space, processor architecture, etc., you will be able to write more efficient programs and gain a huge advantage over other programmers in the process.

If you want to become a better developer, learning C(C) is a great way to start!

By the end of this course, you will understand the basics of the C programming language and make yourself more accessible to entry-level programming positions.

You will understand variables and different data types, be able to use functions and arrays, understand the concept of pointers, learn about control flow (decisions and iterations).

You will be able to apply for real-time programming positions and really understand the core language that most modern languages ​​are based on!

If you have previously used the C(C) programming language, then this course will deepen your understanding. If you've never used it, no problem, you'll see that it can help you become a more efficient developer.

This course does not skip details. You will learn how to write high quality code and become a great problem solver. This course not only introduces how to write in the C programming language, but also includes all the details about "why" you do what you do. At the end of this course, you will fully understand the concepts of the C(C) programming language.

Your teacher Jason Fedin has been teaching students for over 12 years via online platforms at over 10 different online universities. He has created many different curricula ranging from mobile programming to bash to object oriented design and of course the C(C) programming language.

In addition, he has been developing software for over 16 years in the real world in various companies specializing in object-oriented development and mobile applications.

This means that you are learning from someone who has all the training, skills and experience.

If you're ready to land that first paid programming job or move into a more senior programming position, then this course is for you!

1 vote

Hello dear readers!

There are legends about the earnings of programmers. About the opportunity to work as a freelance developer (that is, in pajamas and having a cup of coffee or on the ocean), too. These legends are believed and they want to get into this sphere.

It fuels interest that the programmers themselves say that the path to the profession is open to everyone, not just techies. The main thing is to know where to find it. Are you interested in them too? Then this article describing programming for dummies is for you!

Is it given to everyone

Woody Allen once said that most of life is window dressing. Everyone wants to write a book, a script (program), but few people get beyond their desires, but in vain. If you have started, you are halfway to completion. And there is no need to postpone the start until tomorrow, next month or Monday and look for reasons not to implement the idea right now.

There would be a desire. This is also confirmed by the publication on Habré, which was written by a blind programmer. Blind, but experienced and able to code well. We live in the 21st century, which means we have a sea of ​​opportunities.

The right start is half the battle

To the question of what is needed in order to learn programming from scratch and then earn money with it, the gurus answer: "Assimilation of the basics, which are subsequently found in work everywhere." This:

• algorithm;
• function;
• cycle;
• condition.

Having dealt with them, it will be possible to understand how the program works and how to implement its algorithms in practice. You can find this knowledge yourself in books. But it is even more important to choose a language and decide on the direction of programming.

What language to start

Most technical universities start with slightly outdated languages. These can be Turbo Pascal and Turbo C. Programmers themselves practically do not use them now, but these languages ​​​​justify the purpose of learning. They help students understand the intricacies of working with working memory and help them understand the path they need to take in order to transform an idea into a working program.

In addition, the same C language is a kind of basis for creating modern languages ​​and it is very useful for a future programmer to study it.

If you are interested in promising programming languages, pay attention to:

• Python. By the way, many novice programmers start with it. The secret of its popularity is not in the extensive functionality, but in the ability to quickly start practicing. To get started, just download the file and run it. Understanding the intricacies of the work is also easy: there are a lot of books written in Python. By the way, this language is used in many large companies, and those who are well versed in it can always find a job.
• Java. Very popular, applicable on all devices and platforms. Specialists who have mastered it are in demand and will always be able to find a highly paid position. By the way, it has nothing to do with JavaScript.
• PHP. . It is called a “not quite real” programming language, since it is exclusively designed for the web, while at the same time it is rarely used in web applications. The language is at the heart of the most popular "engines", or CMS. (In this post, I already wrote about what, but here you can see,) Therefore, if you deal with it, and then with WordPress, which is one of the most popular content management systems, you will always find a job for yourself. .

There are other languages: Ruby (like Python scripting), C# (similar in functionality to Java, allows you to create sites and applications on the .NET framework), C ++ (a complex version of C, which opens up a lot of possibilities, which are better to deal with with a mentor).

How to study

There are three ways to learn the basics of programming without having any skills.

self-education

In this case, in your free time you will need to read books, for example:

• “Learning PHP and MySQL” by L. Bailey and M. Morrison;
• « Plain Python. Modern programming style» B. Lubanovich and others.

Then put the acquired knowledge into practice. Then in a year or two, subject to diligent study, it will be possible to master the profession for free. The main thing is to remember why it all started and constantly practice.

This is the most difficult path for beginners, so only a person who lives with an idea, sincerely loves programming and can figure it out on his own can overcome it.

Help from a mentor

A mentor is an experienced programmer who will guide you on the right path. He will advise literature, and check the code, and give tasks for practicing practical skills. The main thing is to find it. Where? Forums, online conferences. Moreover, to find and interest to work with you.

Trainings

To succeed in programming, you need to practice a lot, using theory in practice. This course is based on Geek Brains . With it, you can learn to code for free by watching tutorial videos and doing your homework.

A huge plus is communication with like-minded people. This not only inspires, but also helps to develop: in the team there are more difficulties and mistakes that mentors teach you to cope with. Knowing about them means being one step ahead of your competitors.

Where to go

Where to start learning? From the choice of direction, which will prompt the choice of language. There is:

• Web programming is a promising and rapidly developing field that requires only a computer and a browser to work with. Allows you to create and maintain websites. Having mastered it, you will acquire a specialty thanks to which you can earn good money. Do you want to be a web programmer? Learn PHP.
• Development of programs and applications. A complex, but interesting direction, which is almost impossible to understand without knowing the basics. The choice of language depends on the scope: mobile, for Android () or another platform. Java will do.
• System administration. Everything is simple here: you need to configure programs previously created by someone. In this direction, diversified development is important.

The path to success in all cases lies through the ability to improve and self-develop.

Therefore, subscribe to the blog to constantly receive a portion of useful information and per group In contact with . And also constantly apply knowledge in practice: “write” for yourself, solve problems on the network for programmers, and finally, look for where the recruitment of newcomers to the pro team on freelance exchanges is going.

These tutorials are for everyone, whether you're new to programming or you already have extensive programming experience in other languages! This material is for those who want to learn the C / C ++ languages ​​from its very basics to the most complex structures.

C++ is a programming language, knowledge of this programming language will allow you to manage your computer at the highest level. Ideally, you can make the computer do whatever you want. Our site will help you learn the C++ programming language.

Installing /IDE

The very first thing you should do before you start learning C++ is to make sure you have an IDE - an integrated development environment (the program in which you will program). If you do not have an IDE, then you are here. When you decide on an IDE, install it and practice creating simple projects.

Introduction to C++

The C++ language is a set of commands that tell the computer what to do. This set of commands is usually called source code or just code. Commands are either "functions" or "keywords". Keywords (C/C++ reserved words) are the basic building blocks of the language. Functions are complex building blocks because they are written in terms of simpler functions, as you'll see in our very first program below. This structure of functions resembles the contents of a book. The table of contents can show the chapters of the book, each chapter in the book can have its own table of contents consisting of paragraphs, each paragraph can have its own subparagraphs. Although C++ provides many common functions and reserved words that you can use, there is still a need to write your own functions.

In what part of the program did you start? Each program in C++ has one function, it is called the main or main-function, the execution of the program begins with this function. From the main function, you can also call any other functions, whether they are written by us or, as mentioned earlier, provided by the compiler.

So how do you access these Standard Functions? To get access to the standard functions that come with the compiler, you need to include the header file using the preprocessor directive - #include . Why is it effective? Let's look at an example of a working program:

#include << "Моя первая программа на С++\n"; cin.get(); }

Let's take a closer look at the elements of the program. #include is a "preprocessor" directive that tells the compiler to put the code from the iostream header file into our program before creating the executable. By including a header file in your program, you get access to many different functions that you can use in your program. For example, the cout statement requires an iostream . The line using namespace std; tells the compiler to use a group of functions that are part of the std standard library. This line also allows the program to use operators such as cout . The semicolon is part of the C++ syntax. It tells the compiler that this is the end of the command. You'll see a little later that the semicolon is used to terminate most commands in C++.

The next important line of the program is int main() . This line tells the compiler that there is a function named main , and that the function returns an integer of type int . Curly braces ( and ) signal the start ( and end ) of a function. Curly braces are also used in other blocks of code, but they always mean the same thing - the beginning and end of the block, respectively.

In C++, the cout object is used to display text (pronounced "cout"). He uses characters<< , известные как «оператор сдвига», чтобы указать, что отправляется к выводу на экран. Результатом вызова функции cout << является отображение текста на экране. Последовательность \n фактически рассматривается как единый символ, который обозначает новую строку (мы поговорим об этом позже более подробно). Символ \n перемещает курсор на экране на следующую строку. Опять же, обратите внимание на точку с запятой, её добавляют в конец, после каждого оператора С++.

The next command is cin.get() . This is another function call that reads data from the input data stream and waits for the ENTER key to be pressed. This command keeps the console window from closing until the ENTER key is pressed. This gives you time to look at the output of the program.

Upon reaching the end of the main function (the closing curly brace), our program will return the value 0 for the operating system. This return value is important because, by parsing it, the OS can judge whether our program completed successfully or not. A return value of 0 means success and is returned automatically (but only for the int data type, other functions require you to return the value manually), but if we wanted to return something else, like 1, we would have to do it manually.

#include using namespace std; int main() ( cout<<"Моя первая программа на С++\n"; cin.get(); return 1; }

To consolidate the material, type the program code in your IDE and run it. After the program has run and you've seen the output, experiment a bit with the cout statement. This will help you get used to the language.

Be sure to comment on your programs!

Add comments to the code to make it clearer not only for yourself but also for others. The compiler ignores comments when executing code, which allows any number of comments to be used to describe actual code. To create a comment use either // , which tells the compiler that the rest of the line is a comment, or /* followed by */ . When you're learning to program, it's useful to be able to comment on certain sections of code in order to see how the result of the program changes. You can read in detail about the commenting technique.

What to do with all these types of variables?

Sometimes it can be confusing to have multiple variable types when it seems like some variable types are redundant. It is very important to use the correct variable type, as some variables require more memory than others. Also, because of the way in which floating point numbers are stored in memory, the float and double data types are "imprecise" and should not be used when an exact integer value must be stored.

Declaring Variables in C++

To declare a variable, use the syntax type<имя>; . Here are some examples of variable declarations:

int num; character; float num_float;

It is allowed to declare several variables of the same type in one line, for this each of them must be separated by a comma.

int x, y, z, d;

If you've looked closely, you may have seen that a variable declaration is always followed by a semicolon. You can read more about the convention - "on naming variables".

Common Mistakes When Declaring Variables in C++

If you try to use a variable that is not declared, your program will not compile and you will get an error. In C++, all language keywords, all functions, and all variables are case sensitive.

Using Variables

So now you know how to declare a variable. Here is an example program demonstrating the use of a variable:

#include using namespace std; int main() ( int number; cout<< "Введите число: "; cin >>number; cin.ignore(); cout<< "Вы ввели: "<< number <<"\n"; cin.get(); }

Let's take a look at this program and study its code, line by line. The int keyword says that number is an integer. The cin >> function reads the value in number , the user must press enter after the entered number. cin.ignore() is a function that reads a character and ignores it. We have organized our input into the program, after entering a number, we press the ENTER key, the character which is also passed to the input stream. We don't need it, so we discard it. Keep in mind that the variable was declared to be of type integer, if the user tries to enter a decimal number it will be truncated (i.e. the decimal part of the number will be ignored). Try entering a decimal number or character sequence when you run the example program, the answer will depend on the input value.

Note that quote marks are not used when printing from a variable. The absence of quotes tells the compiler that there is a variable, and therefore that the program must check the variable's value in order to replace the variable's name with its value when executed. Multiple shift operators on the same line are perfectly acceptable and the output will be done in the same order. You must separate string literals (quoted strings) and variables, giving each a different shift operator<< . Попытка поставить две переменные вместе с одним оператором сдвига << выдаст сообщение об ошибке . Не забудьте поставить точку с запятой. Если вы забыли про точку с запятой, компилятор выдаст вам сообщение об ошибке при попытке скомпилировать программу.

Changing and comparing values

Of course, no matter what data type you use, variables are of little interest unless their value can be changed. The following shows some of the operators used in conjunction with variables:

• * multiplication,
• - subtraction,
• + addition,
• / division,
• = assignment,
• == equality,
• > more
• < меньше.
• != not equal
• >= greater than or equal
• <= меньше или равно

Operators that perform mathematical functions must be used to the right of the assignment sign, in order to assign the result to the variable on the left.

Here are some examples:

A = 4 * 6; // use line comment and semicolon, a is 24 a = a + 5; // equals the sum of the original value and five a == 5 // not assigned five, check, and equal to 5 or not

You will often use == in constructs such as conditional statements and loops.

A< 5 // Проверка, a менее пяти? a >5 // Check if a is greater than five? a == 5 // Check if a is five? a != 5 // Check if a is not equal to five? a >= 5 // Check if a is greater than or equal to five? a<= 5 // Проверка, a меньше или равно пяти?

These examples do not show the use of comparison signs very clearly, but when we begin to study selection operators, you will understand why this is necessary.