HDU 1002 大整数相加

#include<stdio.h>#include<string.h>int main(){char a[1000],b[1000],c[1001];int i,j=1,p=0,n,n1,n2;scanf("%d",&n);    while(n){scanf("%s %s",a,b);printf("Case %d:\n",j);printf("%s + %s = ",a,b);n1=strlen(a)-1;n2=strlen(b)-1;for(i=0; n1>=0 || n2>=0; i++,n1--,n2--){if(n1>=0 && n2>=0){c[i]=a[n1]+b[n2]-'0'+p;}if(n1>=0 && n2<0){c[i]=a[n1]+p;}if(n1<0 && n2>=0){c[i]=b[n2]+p;}p=0;if(c[i]>'9'){c[i]=c[i]-10;p=1;}}if(p==1){printf("%d",p);}while(i--){printf("%c",c[i]);}j++;if(n!=1){printf("\n\n");}else {printf("\n");}n--;}}