题解 | #八进制#

#include<iostream>
#include<cstdio>
#include<string>
#include<vector>
using namespace std;
string str;
char inttochar(int x){              //数字转字符
    if(x<10){
        return x+'0';
    }
    else{
        return x-10+'a';
    }
}
int chartoint(char c){             //字符转数字
    if(c>='0'&&c<='9'){
        return c-'0';
    }
    else{
        return c-'A'+10;
    }
}
int main(){
    while(cin>>str){
            long long number=0;
    vector<char>answer;
    for(int i=0;i<str.size();++i){          //把输入转成十进制
        number*=10;
        number+=chartoint(str[i]);
    }
    while(number!=0){
        answer.push_back(inttochar(number%8));     //十进制转八进制，并写入向量中
        number/=8;
    }
    for(int i=answer.size()-1;i>=0;--i){            //逆序输出答案
        printf("%c",answer[i]);
    }
    printf("\n");
        }
    return 0;
}