Structure of a C++ program - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the starting point of execution in a C++ program?

The main() function is the starting point where the program begins execution.

beginner

What is the purpose of #include directives in a C++ program?

They tell the compiler to include the contents of a file, usually a library, so you can use its functions and features.

beginner

What does using namespace std; do in a C++ program?

It allows you to use names from the std namespace (like cout and endl) without writing std:: before them.

beginner

Identify the parts of this simple C++ program:<br>

#include <iostream>
using namespace std;

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

1. #include <iostream> - includes input/output library.<br>2. using namespace std; - allows using standard names.<br>3. int main() - main function where execution starts.<br>4. cout << "Hello, world!" << endl; - prints text.<br>5. return 0; - ends the program successfully.

beginner

Why do we write return 0; at the end of main()?

It tells the operating system that the program finished successfully. Zero usually means no errors.

Which function is the entry point of every C++ program?

A main()

B start()

C init()

D begin()

The main() function is where execution starts in C++.

What does #include <iostream> do?

A Defines the main function

B Includes input/output functions

C Starts the program

D Declares variables

It includes the standard input/output library so you can use cout and cin.

What is the purpose of using namespace std;?

A To declare variables

B To include the standard library

C To start the program

D To avoid writing <code>std::</code> before standard names

It lets you use standard library names without the std:: prefix.

What does return 0; mean in main()?

A Program ended successfully

B Program has an error

C Start the program

D Declare a variable

Returning zero signals successful program completion to the operating system.

Which line prints text to the screen in this code?<br>

int main() {
  cout << "Hi!" << endl;
  return 0;
}

A return 0;

B int main()

C cout << "Hi!" << endl;

D endl;

The cout line sends text to the screen.

Describe the basic structure of a simple C++ program and explain the role of each part.

Think about what each line does from top to bottom.

Why is the main() function important in C++? What happens if it is missing?

Consider what the computer looks for to start running your code.