Structure of a C++ program

Introduction

A C++ program needs a clear structure so the computer knows where to start and what to do step by step.

When writing any new C++ program from scratch.

When organizing code to make it easy to read and understand.

When learning how C++ programs run from start to finish.

When debugging to find where the program begins and ends.

When sharing code with others to follow a common format.

Syntax

C++

#include <iostream>

int main() {
    // Your code here
    return 0;
}

#include <iostream> tells the program to use input and output features.

int main() is the starting point where the program begins running.

Examples

This program prints a greeting message to the screen.

C++

#include <iostream>

int main() {
    std::cout << "Hello, world!" << std::endl;
    return 0;
}

This program shows how to store a number and print it.

C++

#include <iostream>

int main() {
    int number = 5;
    std::cout << "Number is: " << number << std::endl;
    return 0;
}

Sample Program

This simple program prints a welcome message to the screen. It shows the basic structure needed to run any C++ code.

C++

#include <iostream>

int main() {
    std::cout << "Welcome to C++ programming!" << std::endl;
    return 0;
}

Important Notes

The main function must return an integer, usually 0 means the program ended successfully.

Every statement ends with a semicolon ; in C++.

Use std::cout to print text to the screen, and std::endl to move to the next line.

Summary

A C++ program starts running from the main function.

Include necessary libraries like <iostream> for input/output.

Use curly braces { } to group the code inside main.