Hi, i'm a c beginner and have to write a programme to count the number of prime numbers less than 100,1000,10000,100000,1000000 respectively. I've written the following programme but when i run it i keep getting seros! please help!
floor() is a function which returns the integer value of the number.

#include<catam.h> //software library of my university


/*Function test prime tod etermine if number is prime or not. Returns Value called result =1for prime, 0 for non prime*/

double testprime(double h)
{
  double result=1 ,a,i=2;// default result =0, i starts at 2 to avoid dividing my 1 and always gettin an integer
  double x,m;
  m=sqrt(h);
  do
    {
      x=h/(i);
      a=floor(x);

      if(x==a) //if x is integer, result=o ie not prime
    { result=0; }
     i++;

    }
  while(i<=m); //we only divide my i when i less than root(h)

  return result;
  }




/*function countprime counts the number of primes in the value given returns a count*/

double countprime(double a)
{
  double nprime,n, i=2,result=nprime;
  nprime=0;
  do
    {
      result=testprime(i);

      if(result==1) //if number is prime, add one to total of primes
    {
      nprime=nprime+1;
    }
      i=i+1;

    }

  while (i<=a); //only go as far as a
    return nprime;
}

int main(void)
{int j=1;
  double a[5],nprimes[5];
  a[1]=100;
  a[2]=1000;
  a[3]=10000;
  a[4]=100000;
  a[5]=1000000;

do


{
   nprimes[j]=countprime(a[j]);

   printf("%4d\n",nprimes[j]); //print number of primes for value of a
   j++;
}
 while (j<=5);




}