十六进制转八进制

题目链接：http://lx.lanqiao.cn/problem.page?gpid=T51

demo：

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

int main()
{
    int Number;
    cin >> Number;
    for(int k = 1; k <= Number; k++) {
        string String_Hex, String_Binary;
        cin >> String_Hex;
        String_Binary = "";
        for(int i = 0;i < String_Hex.length(); i++){
            switch(String_Hex[i]) {
                case '0':String_Binary += "0000"; break;
                case '1':String_Binary += "0001"; break;
                case '2':String_Binary += "0010"; break;
                case '3':String_Binary += "0011"; break;
                case '4':String_Binary += "0100"; break;
                case '5':String_Binary += "0101"; break;
                case '6':String_Binary += "0110"; break;
                case '7':String_Binary += "0111"; break;
                case '8':String_Binary += "1000"; break;
                case '9':String_Binary += "1001"; break;
                case 'A':String_Binary += "1010"; break;
                case 'B':String_Binary += "1011"; break;
                case 'C':String_Binary += "1100"; break;
                case 'D':String_Binary += "1101"; break;
                case 'E':String_Binary += "1110"; break;
                case 'F':String_Binary += "1111"; break;
                default:break;
            }
        }
        if(String_Binary.length() % 3 == 1) String_Binary = "00" + String_Binary;
        else if(String_Binary.length() % 3 == 2) String_Binary = '0' + String_Binary;
        int Sign_Leading_Zero = 0;
        for(int i = 0;i <= String_Binary.length() - 3; i += 3){
            int Digit_Number = 4 * (String_Binary[i] - '0') + 2 * (String_Binary[i+1] - '0') + (String_Binary[i+2] - '0');
            if(Digit_Number) Sign_Leading_Zero = 1;
            if(Sign_Leading_Zero) cout << Digit_Number;
        }
        cout << endl;
    }
    return 0;
}