估算pi的近似值，不知哪里出现了问题，特来提问，结果是0

#include
#include
#include
#include
int main()
{
long k=0,c=0,d=0;
double pi=0.0,x=0.0,y=0.0;
srand((unsigned int)time(NULL));
for(k=0;k<10000000;k++){
d++;
x=(double)rand()/32767.0;
y=(double)rand()/32767.0;
if(sqrt(x*x+y*y)<=1.0)
c++;
}
pi=4.0*c/d;
printf("the aproximate value of pi is %18.14lf\n",pi);
}

#include<stdio.h> 
#include<math.h> 
#include<stdlib.h> 
#include<time.h>

int main()
{
long k=0,c=0,d=0;
double pi=0.0,x=0.0,y=0.0;
srand((unsigned int)time(NULL));
for(k=0;k<10000000;k++){
d++;
x = rand() / (double)RAND_MAX;
y = rand() / (double)RAND_MAX;
if(sqrt(x*x+y*y)<=1.0)
c++;
}
pi=4.0*(double)c/(double)d;
printf("the aproximate value of pi is %18.14lf\n",pi);
}