问基本C++计算器

EN

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

int main()
{
    int x;
    int v;
    int sum;
    string input;
    cout << "Choose arithmetic: addition or subtraction? " << endl;
    cin >> input;
    if(input=='Addition'||input=='addition')
    {
        int first;
        int second;
        int sum = first+second;
        cout << "Enter the first number: " << endl;
        cout << "Enter the second number: " << endl;
        cout << "The sum of these numbers is: " << sum << endl;
    }

    return 0;
}