题解 | #进制转换#

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

int main() {
    string str;
    while (cin >> str) {
        string x(str, 2);
        int sum = 0;
        for (int i = 0; i < x.size(); i++) {
            int num = (int)x[i];
            if (num >= 48 && num <= 57) {	//ascii里指0-9
                num -= 48;
            }
            if (num >= 65 && num <= 70) {	//ascii里指A-F
                num -= 55;
            }
            sum = sum * 16 + num;
        }
        cout<<sum<<endl;
    }
}
// 64 位输出请用 printf("%lld")