怎么判断一个数是整数还是浮点数

double modf(double x,double * ip)

把x分成整数和小数两部分，两部分正负与x相同，函数返回小数部分，整数部分保存在*ip中

函数名:  modf

功 能: 把数分为整数和小数 （The  modf function breaks down the floating-point value  x into fractional and integer parts, each of which has the same sign as  x. The signed fractional portion of x is returned. The integer portion is stored as a floating-point value at  intptr.

）

用 法:  double modf(double x, double *intptr);

程序例:

#include

#include

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\n",

number, integer, fraction);

return 0;

}