C程序计算奇数位数和偶数位数之差

Input:12345
Output:3

the odd digits is 2+4=6
the even digits is 1+3+5=9
odd-even=9-6=3

#include 
using namespace std;
int main() {
   int n, r=0;
   int diff =0;
   int even=0;
   int odd=0;
   n=12345;
   while(n != 0){
      r = n%10;
      if(r % 2 == 0) {
         even+=r;
      } else {
         odd+=r;
      }
      n/=10;
   }
   diff=odd-even;
   printf("%d",diff);
   return 0;
}