Implement Power Function

int Solution::pow(int x, int n, int d) {
    // Do not write main() function.
    // Do not read input, instead use the arguments to the function.
    // Do not print the output, instead return values as specified
    // Still have a doubt. Checkout www.interviewbit.com/pages/sample_codes/ for more details
    
    if(n==0)
       return 1%d;
       
    if(n==1)
      return (x+d)%d;
       
    long long  ans=1,base=x;
    
    while(n>0)
    {
        if(n%2==1)
          {
              ans=(ans*base)%d;
          
             n--;
          }
          else
          {
              base=(base*base)%d;
              n=n/2;
          }
    }
    
   if(ans<0)
   {
       ans=(ans+d)%d;
   }
    return ans;
    
}