大数字问题

#include "stdio.h"
#include "string.h"
main()
{
	int a[1010] = {0},b[1010] = {0},c[1010] = {0};
	int i,j,d,l1,l2,T,tem;
	char s1[1010],s2[1010];
	scanf("%d",&T);
	tem = 1;
	while(tem <= T)
	{
		scanf("%s%s",s1,s2);
		l1 = strlen(s1);
		l2 = strlen(s2);
		for(i=0; i<l1; i++)
		{
			a[l1-1-i] = s1[i] - '0'; 
		} 
		for(i=0; i<l2; i++)
		{
			b[l2-1-i] = s2[i] - '0';
		}
		d = 0;
		for(i=0; (i<=l1 || i<=l2); i++)
		{
			c[i] = (a[i] + b[i] + d) % 10;
			d = (a[i]+ b[i] + d)>9 ? 1:0;
		}	
		while(c[i] == 0)	{i--; }
		printf("Case %d:\n",tem++);
		printf("%s + %s = ",s1,s2);
		while(i>=0) {printf("%d",c[i]);i--;	}
		printf("\n");
		if(tem<=T)	printf("\n");
	}
	return 0;
}