PAT Basic Level 1016. 部分A+B (15)

#include <iostream>
#include <string>
using namespace std;

int main()
{
string a, b;
char da, db;
cin >> a >> da >> b >> db;

int numa = 0;
int basea = da - '0';
for (int i = 0; i < a.length(); ++i){
if (a[i] == da){
numa = numa*10+basea;
}
}

int numb = 0;
int baseb = db - '0';
for (int i = 0; i < b.length(); ++i){
if (b[i] == db){
numb = 10*numb+baseb;
}
}

cout << numa + numb << endl;

system("pause");
return 0;
}