【关键在于怎么把大数读入数组（用一个char型变量做辅助）】

#include 
     
       #include 
      
        #define M 10 #define N 1000 void add(int *a,int *b,int *c)//加法 {
   int i,carry=0; for (i=N-1;i>=0;i--)     {
           c[i]=a[i]+b[i]+carry; if (c[i]>=M)         {
               c[i]-=M;             carry = 1;         } else         {
               carry = 0;         }     } } void con(int *a,int *c)//转换 {
   int i,j;     i=0; while (c[i]==0)         i++;     j=999; while (i<=999)         a[j--]=c[i++]; } void main() {
   int a[1000],b[1000],c[1000],i; char ch;     memset(a,0,sizeof(a));     memset(b,0,sizeof(b));     i=999;     memset(c,0,sizeof(c)); while ((ch=getchar())!='\n')         c[i--]=ch-48;     con(a,c);     i=999;     memset(c,0,sizeof(c)); while ((ch=getchar())!='\n')         c[i--]=ch-48;        con(b,c);     memset(c,0,sizeof(c));     add(a,b,c);     i=0; while (c[i]==0)         i++; while (i<=999)         printf("%d",c[i++]);     printf("\n"); }