杭电2031进制转换

#include <cstdlib>

#include <iostream>

#include <math.h> 

using namespace std;



int main(int argc, char *argv[])

{

    int n,r;

    int Remainder[100]={0};

    while(cin>>n>>r)

    {

       int flag=0,t=n,k=0,Quotient=n;

       if(n>=0&&n<=r)

         cout<<n<<endl;

       if(n>r)

       {

         while(Quotient!=0)

         {

           Quotient=Quotient/r;

           k++;

         }

         Quotient=n;

         for(int i=0;i<k;i++)

         {

           Quotient=Quotient/r;

           if(Quotient>=0)

           {

             Remainder[i]=t%r; 

             t=t/r;

           }  

         }

         flag=1; 

       } 

       if(n<0)

       {  

         n=abs(n); 

         Quotient=n;

         t=n; 

         while(Quotient!=0)

         {

           Quotient=Quotient/r;

           k++;

         }

         Quotient=n;

         for(int i=0;i<k;i++)

         {

           Quotient=Quotient/r;

           if(Quotient>=0)

           {

             Remainder[i]=t%r; 

             t=t/r;

           }  

         }

         flag=0; 

       } 

       if(flag==1)

       {

         for(int i=k-1;i>=0;i--)

         {

           if(Remainder[i]==10)

             cout<<'A';

           if(Remainder[i]==11)

             cout<<'B';

           if(Remainder[i]==12)

             cout<<'C';

           if(Remainder[i]==13)

             cout<<'D';

           if(Remainder[i]==14)

             cout<<'E';

           if(Remainder[i]==15)

             cout<<'F';

           if(Remainder[i]>=0&&Remainder[i]<=9) 

             cout<<Remainder[i];     

         }

         cout<<endl;     

       } 

       if(flag==0)

       {

         cout<<"-" ; 

         for(int i=k-1;i>=0;i--)

         {

           if(Remainder[i]==10)

             cout<<'A';

           if(Remainder[i]==11)

             cout<<'B';

           if(Remainder[i]==12)

             cout<<'C';

           if(Remainder[i]==13)

             cout<<'D';

           if(Remainder[i]==14)

             cout<<'E';

           if(Remainder[i]==15)

             cout<<'F';

           if(Remainder[i]>=0&&Remainder[i]<=9) 

             cout<<Remainder[i];  

         } 

         cout<<endl; 

       } 

    }

    system("PAUSE");

    return EXIT_SUCCESS;

}

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2031
以上代码主要分为三个部分：1.n>r;2.0<n<=r;3.n<0;(n是十进制数，r是进制)