hdu 2031 进制转换

#include<cstdio>#include<iostream>using namespace std;string transform(int x,int y,string s){    string res="";    int sum=0;    for(int i=0;i<s.length();++i){        if(s[i]=='-')           continue;        if(s[i]>='0'&&s[i]<='9'){           sum=sum*x+s[i]-'0'                             ;        }        else{          sum=sum*x+s[i]-'A'+10;        }    }        while(sum){           char tmp=sum%y;           sum/=y;           if(tmp<=9){             tmp+='0';           }           else{             tmp=tmp-10+'A';           }           res=tmp+res;        }        if(res.length()==0)          res="0";        if(s[0]=='-')           res='-'+res;        return res;}int main(){   string s;   int n;   while(cin>>s){     cin>>n;     string str=transform(10,n,s);     cout<<str<<endl;   }}