Maximum Occurred digit

#include <stdio.h>
#include <math.h>
//this code gives the maximum occurred digit in a given integer as output
//If there's 2 integer repeating for the same time, the code will add them and give that as output
int main()
{
    int num,n_num,o,d,i,count;
    int max=0, max_o=0, zero=0;
    scanf("%d",&num);
    for(;num>0;){
        d=num%10;
        n_num=0,i=0,count=0;
        while(num>0){
          o=num%10;
          if(o==d){
            count++;
          }
          else if(o==0){
            zero++;
          }
          else{
            n_num=n_num+(o*pow(10,i));
            i++;
          }
          num=num/10;
        }
        num=n_num;
        if(zero>max){
            max=zero;
            max_o=0;
        }
        else if(count>max){
            max=count;
            max_o=d;
        }
        else if(count==max){
            max_o=max_o+d;
        }
    }
    printf("%d",max_o);
    return 0;
}