主要就是分支的考察吧

#include <iostream>

using namespace std;

int main(){
    int k;
    int a, b;
    while (scanf("%d", &k) && k != 7){
        if (k == 1){
            char op; int v;
            cin >> op >> v;
            if (op == 'A') a = v;
            else b = v;
        }else if (k == 2){
            char op;
            cin >> op;
            if (op == 'A') cout << a << endl;
            else cout << b << endl;
        }else if (k == 3){
            char op1, op2;
            cin >> op1 >> op2;
            if (op1 == op2){
                if (op1 == 'A') a *= 2;
                else b *= 2;
            }else {
                if (op1 == 'A') a = a + b;
                else b = b + a;
            } 
        }else if (k == 4){
            char op1, op2;
            cin >> op1 >> op2;
            if (op1 == op2){
                if (op1 == 'A') a = a * a;
                else b = b * b;
            }else {
                if (op1 == 'A') a = a * b;
                else b = b * a;
            }
        }else if (k == 5){
            char op1, op2;
            cin >> op1 >> op2;
            if (op1 == op2){
                if (op1 == 'A') a = 0;
                else b = 0;
            }else {
                if (op1 == 'A') a = a - b;
                else b = b - a;
            }
        }else if (k == 6){
            char op1, op2;
            cin >> op1 >> op2;
            if (op1 == op2){
                if (op1 == 'A') a = 1;
                else b = 1;
            }else {
                if (op1 == 'A') a = a / b;
                else b = b / a;
            }
        }
    }

    return 0;
}