Integer division in C++ truncates any fractional part of the result. The modulus operator (%) returns the remainder of an integer division. For example, 17 % 3 is 2, because the remainder of 17 divided by 3 is 2. The modulus operator allows retaining the remainder instead of dropping it during integer division.

1. 9% 4 is 1
cout yield to display modulu1:
the following statement a string and a
value, to cout:
17 % 3 is 2 (the remainder when 17 is
divided by 3 is 2)

2. 14 % 2 is 0 (the remainder when 14 is
divided by 2 is 0)
Integer Division
The division of two integer values can
produce rather strange results for the
unwary. For example, the expression 15/2
yields the integer result 7.

3. Because integers can’t contain a fractional
part, the value 7.5 can’t be obtained. The
fractional part resulting when two integers
are divided—the remainder—is always
dropped (truncated).
Therefore 9/4 is 2.
And 20/3 is 6.

4. You need to retain the remainder of an integer
division.
C++ provides the modulus operator (also
referred to as the “remainder operator”),
This operator captures the remainder when an
integer is divided by an integer; using a non-integer
value with the modulus operator results in a
compiler error.