藍橋杯基礎練習 十六進制轉八進制

剛開始用java寫了一個，後來發現一個用C++也不難的代碼，分享下

#include <iostream>
#include <string>
#include <cstring>
using namespace std;
string s1,s2;


int main(){
int n,i,j,len,len1;
int num;
cin >> n;
for (i=0; i<n; i++){
cin >> s1;
len=s1.length();

s2="";
for (j=0; j<len; j++){
switch(s1[j])
{
case '0':s2+="0000";break;
case '1':s2+="0001";break;
case '2':s2+="0010";break;
case '3':s2+="0011";break;
case '4':s2+="0100";break;
case '5':s2+="0101";break;
case '6':s2+="0110";break;
case '7':s2+="0111";break;
case '8':s2+="1000";break;
case '9':s2+="1001";break;
case 'A':s2+="1010";break;
case 'B':s2+="1011";break;
case 'C':s2+="1100";break;
case 'D':s2+="1101";break;
case 'E':s2+="1110";break;
case 'F':s2+="1111";break;
default:break;
}
}
len1=s2.length();
if (len1%3 == 1)
s2="00"+s2;
else if (len1 % 3 == 2)
s2="0"+s2;
len1=s2.length();
int flag=0;
for(j=0;j<=len1-3;j+=3)
{
num=(s2[j]-'0')*4+(s2[j+1]-'0')*2+s2[j+2]-'0';
if (num != 0) flag=1;
if(flag) cout << num;
}
cout << endl;
}
return 0;
}