Input 12457output 1+7=8input 55529output 5+9=14java или с++

#include <iostream>

#include <cstring>

using namespace std;

int main(){

   string num;

   int sum;

   cout<<"Input number:"<<endl;

   cin>>num;

   sum = num[0] - '0' + num.back() - '0';

   cout<<"Output number: "<< sum << endl;

   return 0;

}