modf
函数名:modf
功 能: 把数分为整数和小数 （Themodffunction breaks down the floating-point valuexinto fractional and integer parts, each of which has the same sign asx. The signed fractional portion of x is returned. The integer portion is stored as a floating-point value atintptr.
）
用 法:double modf(double x, double *intptr);
程序例:
#include <math.h>
#include <stdio.h>
int main(void)
{
double fraction, integer;
double number = 100000.567;
fraction = modf(number, &integer);
printf("The whole and fractional parts of %lf are %lf and %lf
",
number, integer, fraction);
return 0;
}