A variable is a named storage location used to hold data during program execution. Every variable has a data type that determines the kind of value it can store.

This example demonstrates how variables are declared, assigned values, and used in expressions.

Source Code #

#include <iostream>

int main()
{
    int age;

    age = 21;

    std::cout << "Age: " << age << '\n';

    return 0;
}

Output #

Age: 21

Explanation #

• int age; declares a variable named age that can store integer values.
• Declaring a variable allocates storage for the specified data type.
• age = 21; assigns the value 21 to the variable using the assignment operator (=).
• The value stored in a variable can be modified by assigning a new value.
• std::cout << "Age: " << age << '\n'; retrieves the value stored in age and writes it to the standard output stream.
• return 0; terminates the program successfully.