题解 | #进制转换#

#include <iostream>
#include<string>
#include<cstring>
#include<cmath>
using namespace std;
//16进制转换成10进制
int main() {
    string s;
    while (cin >> s) {
        int len = s.size();
        int c2[len];
        for (int i = len - 1; i >= 2; i--) {
            if (s[i] >= 65 && s[i] <= 70) c2[i] = (int)s[i] - 55;
            else if (s[i] >= 97 && s[i] <= 102) c2[i] = (int)s[i] - 87;
            else  c2[i] = s[i] - '0';
        }
        int sum = 0;
        for (int i = len - 1; i >= 2; i--) {
            sum += c2[i] * pow(16, len - 1 - i);
        }
        cout << sum<<endl;
    }
    return 0;
}