CUBEFR-Cube Free Numbers

below given code is for cubefr spoj or Cube Free Numbers spoj.

here u nave to simply apply sieve .

#include<stdio.h>
int A[1000001]={0};
void cube_free()
{
 int i,k,j;
 for(i=2;i<=100;i++)
 {
  if(A[i]==0)
  {
   k=i*i*i;
   for(j=k;j<=1000000;j+=k)
    A[j]=-1;
  }
 }
 k=1;
 for(i=1;i<=1000000;i++)
  if(A[i]==0)
   A[i]=k++;
}
int main()
{
 cube_free();
 int t,n;
 scanf("%d",&t);
 for(int i=1;i<=t;i++)
 {
  scanf("%d",&n);
  if(A[n]!=-1)
   printf("Case %d: %d\n",i,A[n] );
  else
   printf("Case %d: Not Cube Free\n",i);
 }
 return 0;
}