#53 – Modulus
August 9, 2010 Leave a comment
The modulus operator %, used as a binary operator
a % b
is defined as the remainder of a (dividend) divided by b (divisor). Also known as “modulo“.
The idea is to determine the maximum integer that you can multiply b by to get a result <=a. Let’s call this integer n. Then the remainder is just a – (b * n).
Examples:
int n1 = 5 % 2; // 1 [5-(2*2)] int n2 = 39 % 5; // 4 [39-(5*7)] int n3 = 10 % 2; // 0 [10-(2*5)]
If a is equal to b, the remainder is always 0.
If a is less than b, the remainder is always equal to a.
If either a or b is negative, the result always matches the sign of a.
int n5 = -5 % 2; // -1 int n6 = 5 % -2; // 1 int n7 = -5 % -2; // -1
C# also supports the use of the modulus operator for floating point numbers:
double d1 = 42.5 % 12.2; // ~5.9 [42.5-(12.2*3)]
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