Ceiling and Floor a number without using library function's !

ceilAndFloor.c

/* ceiling and floor a number without using library function's */


#include<stdio.h>

int CEIL(double v)
{
    if(v-(int)v==0)    // check weather the float variable contains a integer value or not // 
        return v;
    else
    return FLOOR(v)+1;
}

int FLOOR(double v)
{
    int t;
    if(v<0){
       t=(int)v +(-1);
       return t;
    }
    else return v;
}

int main()
{
    printf("%d",FLOOR(-3.5));
}

Does it work?

Its not working for the long range values even after chaging data type