1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <string.h>
  4 char* BigIntegerAdd(char *s1,int n1,char *s2,int n2)
  5 {
  6     char *result,*p1,*p2;
  7     int c1=n1,c2=n2,length=n1>n2?n1:n2,carry=0;
  8     
  9     p1=s1;
 10     p2=s2;
 11     result=(char *)malloc((length+1)*sizeof(char));
 12 
 13     //make p1,p2,result point to tail
 14     p1=s1+n1-1;
 15     p2=s2+n2-1;
 16     result+=length;
 17     *(result+1)=0;    //mark the end of string
 18     while (p1>=s1 && p2>=s2)
 19     {
 20         if(*p1+*p2+carry-48>57)//有进位
 21         {
 22             *result=*p1+*p2+carry-10-48;
 23             carry=1;
 24         }
 25         else
 26         {
 27             *result=*p1+*p2+carry-48;
 28             carry=0;
 29         }
 30         p1--;
 31         p2--;
 32         result--;
 33     }
 34 
 35     //剩余一串的处理
 36     if (p1<s1)
 37     {
 38         while (p2>=s2)
 39         {
 40             if (*p2+carry>57)
 41             {
 42                 *result=*p2+carry-10;
 43                 carry=1;
 44             }
 45             else
 46             {
 47                 *result=*p2+carry;
 48                 carry=0;
 49             }
 50             p2--;
 51             result--;
 52         }
 53     }
 54     else
 55     {
 56         while (p1>=s1)
 57         {
 58             if (*p1+carry>57)
 59             {
 60                 *result=*p1+carry-10;
 61                 carry=1;
 62             }
 63             else
 64             {
 65                 *result=*p1+carry;
 66                 carry=0;
 67             }
 68             p1--;
 69             result--;
 70         }
 71     }
 72     //最高位是否有进位
 73     if (carry==1)
 74     {
 75         *result=carry+48;
 76     }
 77     else
 78     {
 79         result++; //最高位无进位，指针退一个
 80     }
 81     //puts(result);
 82     return result;
 83 }
 84 void main()
 85 {
 86 
 87     int n,i=1;
 88     char *s1=(char*)malloc(sizeof(char)*1000);
 89     char *s2=(char*)malloc(sizeof(char)*1000);
 90     scanf("%d",&n);
 91     getchar();
 92     while (i<=n)
 93     {
 94         scanf("%s",s1);
 95         scanf("%s",s2);
 96         if (i==n)
 97         {
 98             printf("Case %d:\n%s + %s = %s\n",i,s1,s2,BigIntegerAdd(s1,strlen(s1),s2,strlen(s2)));
 99         }
100         else
101         {
102             printf("Case %d:\n%s + %s = %s\n\n",i,s1,s2,BigIntegerAdd(s1,strlen(s1),s2,strlen(s2)));
103         }
104         
105         i++;
106     }
107 }