some improvements to the prime number printing program.

int main()
{
int i, j;
double sqrti;

printf("%d\n", 2);

for(i = 3; i <= 100; i = i + 2)
 {
 sqrti = sqrt(i);
 for(j = 2; j < i; j = j + 1)
  {
  if(i % j == 0)
   break;   /* not prime */
  if(j > sqrti)
   {   /* prime */
   printf("%d\n", i);
   break;
   }
  }
 }

return 0;
}