Recognizing when to use the modulus operator

Question

I know the modulus (%) operator calculates the remainder of a division. How can I identify a situation where I would need to use the modulus operator?

I know I can u

Answer 1

One use case I saw recently was when you need to reverse a number. So that 123456 becomes 654321 for example.

int number   = 123456;
int reversed = 0;

while ( number > 0 ) {
    # The modulus here retrieves the last digit in the specified number
    # In the first iteration of this loop it's going to be 6, then 5, ...
    # We are multiplying reversed by 10 first, to move the number one decimal place to the left.
    # For example, if we are at the second iteration of this loop, 
    #  reversed gonna be 6, so 6 * 10 + 12345 % 10 => 60 + 5
    reversed = reversed * 10 + number % 10;
    number = number / 10;
}