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C++ Introduction
course content

Course Content

C++ Introduction

C++ Introduction

1. Getting Started
Why to Learn C++What is C++Entry Point of a ProgramStandard Library and FilesPreprocessor DirectivesThe First Program
2. Variables and Data Types
Data TypesUnderstanding VariablesNumerical Data TypesIntroduction to StringIntroduction to ArraysKeywords sizeof(), auto and typedefWorking with the Array
3. Introduction to Operators
Simple OperatorsA Little MathLogical OperatorsCompound Assignment OperatorPracticing Math Basics
4. Introduction to Program Flow
If...else StatementTernary OperatorSwitch StatementWhile LoopDo...while LoopFor LoopFibonacci Number with Loops
5. Introduction to Functions
What are Functions?Type of FunctionsReturn Statement in FunctionsFunctions With Arguments Simple Function

bookEntry Point of a Program

Every C++ program must have a main() function. It serves as the entry point of the program. Without a main() function, the compiler wouldn't know where to start executing the program. It's name is reserved, this means that the function name main() cannot be changed, and it must follow a specific signature for the program to run correctly.

cpp

main

copy

              
1234

            
int main()
{
    return 0;
}
  • int main(): the starting point of a program. It's called the main function, and it's where the program begins executing;
  • { }: curly braces define a block of code. Everything inside these braces belongs to the main function and is part of the program's logic;
  • return 0;: marks the end of the program and indicates that it ran successfully. The 0 means everything went well. If there were issues, this value might be different in the output.

Note

The return 0; statement is optional at the end of the main function. If omitted, the compiler will automatically insert it.

Inside the main() function, you can start writing your code. Every expression should end with a ; symbol so the program can understand when one command finishes and the next one begins.

cpp

main

copy

              
1234

            
int main()
{
    5 + 5;
}

Above, you can see a simple expression. Expressions form the building blocks of statements and define how values are calculated or manipulated in a program. The one above doesn't involve variables, built-in commands, or anything complex, but we will use all of these eventually in the future.

cpp

main

copy

              
123456

            
int main()
{
    5 + 5;
    1 - 8;
    9 / 3;
}

You can write as many expressions as you want, but each has to end with a ;. If you remove the semicolon from 5+5;, C++ will see the expression 5 + 5 1 - 8;, which will not make sense to it and will generate an error. However, you can write all of your code on a single line if you want.

cpp

main

copy

              
1234

            
int main()
{
    5 + 5; 1 - 8; 9 / 3;
}

If you run the code above, nothing will appear on the console. This is because C++ might skip the calculation if it determines the result is unused. Moreover, there is no command to display or store the result.

1. Which of the following statements about the `main()` function is `false`?
2. What does the `return 0;` statement at the end of the `main()` function helps to identify?
3. What happens if you omit semicolons at the end of expressions within the `main()` function?
Which of the following statements about the `main()` function is `false`?

Which of the following statements about the main() function is false?

Select the correct answer

What does the `return 0;` statement at the end of the `main()` function helps to identify?

What does the return 0; statement at the end of the main() function helps to identify?

Select the correct answer

What happens if you omit semicolons at the end of expressions within the `main()` function?

What happens if you omit semicolons at the end of expressions within the main() function?

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 1. Chapter 3
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