C語言 是定義ceil與floor函數，不是調用

#include<stdio.h>

int ceil(float x)

{return (int)(x+1-1e-45);}

int floor(float x)

{return (int)(x-1e-45);}

int main()

{float x=0.000000000001,y=2.999999999;

printf("x=%f ?ceil(x)=%d ?floor(x)=%d\n",x,ceil(x),floor(x));

printf("y=%f ?ceil(y)=%d ?floor(y)=%d\n",y,ceil(y),floor(y));

return 0;

}