C++利用權重方法將二進制正數轉換為十進制數

#include <iostream>
#include <Windows.h>
#include <string>

using namespace std;

int main(void) {
    string str;
    int p = 1; //記錄當前二進制權重
    int s = 0;

    cout << "請輸入一個二進制數：";
    cin >> str;

    for (int i = str.length()-1; i >= 0; i--) {
        int x = str[i] - '0'; // '0' - '0' = 0  '1' - '0' = 1
        s += x * p;
        p *= 2; // p = p * 2
    }
    cout << s << endl;
    system("pause");
    return 0;
}