C Pocket Reference

Mathematical Functions for Integer Types

The mathematical functions for the types int and long are declared in stdlib.h.

int rand( void );

Generates a random number between 0 and RAND_MAX. The constant RAND_MAX has a value of at least 32767, or 2¹⁵ - 1.

void srand( unsigned n );

Initializes the random number generator with the seed n. After this function has been called, calls to rand() generate a new sequence of random numbers.

int abs( int x );

Returns the absolute value of x.

div_t div( int x, int y );

Divides x by y and stores the integer part of the quotient and the remainder in a structure of type div_t, whose members quot (the quotient) and rem (the remainder) have type int. The type div_t is defined in stdlib.h.

The corresponding (to abs() and div()) functions labs() , llabs() ^(*), lldiv() ^(*), and ldiv() are also provided for integers of type long long(*). Furthermore, the functions imaxabs() ^(*) and imaxdiv() ^(*) are defined for the type intmax_t ^(*). These functions are declared in inttypes.h ^(*).