C++ Basics

Conditional structure (if - else)

If statement is used to execute a statement or block, if, and only if, a condition is true.

General syntax:

if ( a condition is true )
{
    Execute all statements inside the braces
}
else
{
    Execute all statements inside the braces if the condition is not true
}

Practical example 1:

#include <iostream>
int main()
{
    int number = 0;
    std::cout << "Please enter a number bigger than 100: " << std::endl;
    std::cin >> number;
    if(number > 100)
    {
        std::cout << "The number is bigger than 100. " << std::endl;
    }
    else
    {
        std::cout << "The number " << number << " is not bigger than 100." << std::endl;
    }
}

The example above showed an if-else statement. If the condition between the parenthesis is false, the code execution jumps directly to the else branch.

Practical example 2:

#include <iostream>
int main()
{
    int number = 0;
    std::cout << "Please enter the number 100: " << std::endl;
    std::cin >> number;
    if(number < 100)
    {
        std::cout << "The number is lower than 100. " << std::endl;
    }
    else if(number == 100)
    {
        std::cout << "Congrats!" << std::endl;
    }
    else if(number > 100)
    {
        std::cout << "The number is bigger than 100." << std::endl;
    }
    else
    {
        std::cout << "Please enter the number 100!" << std::endl;
    }
}

This example shows the if-else if-else conditional structure where one can check multiple cases.