poj 2736 大整数减法

 #include<stdio.h>
#include<string.h>
#include<iostream>
using namespace std;
#define N 110
char str1[N],str2[N];
int a[N],b[N],c[N];
int main()
{
     int n,i,j;
     int len1,len2; cin>>n; while(n--) { memset(a,0,sizeof(a));
         memset(b,0,sizeof(b));
         memset(c,0,sizeof(c));
         cin>>str1>>str2;
         len1=strlen(str1);
         len2=strlen(str2);
         j=0;
         for(i=len1-1;i>=0;i--)
         a[j++]=str1[i]-'0';
         j=0;
         for(i=len2-1;i>=0;i--)
         b[j++]=str2[i]-'0';
         for(i=0;i<len1;i++)
         {
             c[i]+=(a[i]-b[i]);
             if(c[i]<0)
             {
                 c[i+1]--;
                 c[i]+=10;
             }
         }
         i=len1-1;
         while(!c[i])
         {
             i--;
             if(i==-1) break;
         }
         if(i==-1)
         {
             cout<<"0\n";
             getchar();
             continue;
         }
         while(i>=0)
         {
             cout<<c[i];
             i--;
         }
         cout<<endl;
         getchar();
     }

     return 0;
}