Modulo operator in C++

TL ; DR:

• The modulo operator (%) calculates the remainder of dividing two values:

  cout << 10 % 2; // Output: 0
  cout << 15 % 4; // Output: 3
  cout << 20 % 3; // Output: 2
  

  
  

• It can also be used with variables:

  int a = 2;
  int b = 4;
  
  cout << b % a; // Output: 0
  cout << 11 % b; // Output: 3
  

Full lesson:

Remember how we first learn about the division of two integer numbers in primary school?

The quotient is the number of times a division is completed fully, while the remainder is the amount left that doesn't entirely go into the divisor.

Here are some examples:

10 / 2 = quotient 5, remainder 0
15 / 4 = quotient 3, remainder 3
20 / 3 = quotient 6, remainder 2

The modulo operator:

The modulo operator (%) calculates the remainder of dividing two values:

cout << 10 % 2 << endl; // Output: 0
cout << 15 % 4 << endl; // Output: 3
cout << 20 % 3 << endl; // Output: 2

It can also be used with variables:

int a = 2;
int b = 4;

cout << b % a << endl; // Output: 0
cout << 11 % b << endl; // Output: 3

Integral Division:

Remember that in C++, division between integers with / returns only the integral part of the result:

cout << 10 / 2 << endl; // Output: 5
cout << 15 / 4 << endl; // Output: 3
cout << 20 / 3 << endl; // Output: 6

Quotient and remainder:

In programming, we combine both these concepts to get the quotient and remainder of some divison:

// Let's divide 26 by 3:
int quotient = 26 / 3;
int remainder = 26 % 3;

cout << quotient << endl; // Output: 8
cout << remainder << endl; // Output: 2

Assignment
Follow the Coding Tutorial and let's practice with quotient and remainder!

Hint
Look at the examples above if you get stuck.