roman to arabic (probably)

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

int convert(char c) {
    if ((c == 'I') || (c == 'V') || (c == 'X') || (c == 'L') || (c == 'C') || (c == 'D') || (c == 'M')) {
        switch (c) {
        case 'M': return 1000;
        case 'D': return 500;
        case 'C': return 100;
        case 'L': return 50;
        case 'X': return 10;
        case 'V': return 5;
        case 'I': return 1;
        default: return 0;
        }
    }
    else return 0;
}

int translate(const string str) {
    int res = 0; int tmp = 0;
    bool status = true;
    for (int i = 0; i < size(str); i++) {
        int x = convert(str[i]);
        if (tmp == 0) {
            tmp = x;
            res += x;
        }
        else
        {
            if (tmp >= x) {
                res += x;
            }
            else {
                res += x - 2*tmp;
            }
            tmp = x;

        }
    }

    return res;
}

int main() {
    string str;
    cin >> str;
    cout << translate(str);
}