高精度加法

#include<iostream>
//#include<fstream>
#include<string>
using namespace std;
int max(int a,int b)
{
    if(a>b) return a;
    else return b;
}
int main()
{
//    ifstream in("in.dat",ios::in);
    int a[1005],n,i,b[1005],flag,j,w,mlen,la,lb;
    string stra,strb;
    cin>>n;
    for(i=0;i<n;i++)
    {
        cin>>stra>>strb;
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        cout<<"Case "<<i+1<<":"<<endl;
        la=stra.length();
        lb=strb.length();
        mlen=max(la,lb)+1;
        w=0;
        for(j=la-1;j>=0;j--)
            a[w++]=stra[j]-'0';
        w=0;
        for(j=lb-1;j>=0;j--)
            b[w++]=strb[j]-'0';
        for(j=0;j<=mlen;j++)
        {
            a[j]+=b[j];
            if(a[j]>=10)
            {
                a[j]-=10;
                a[j+1]++;
            }
        }    
        flag=0;
        cout<<stra<<" + "<<strb<<" = ";
        for(j=mlen;j>=0;j--)
            if(flag) cout<<a[j];
            else if(a[j])
            {
                cout<<a[j];
                flag=1;
            }
        if(la==1&&lb==1&&stra[0]=='0'&&strb[0]=='0') cout<<'0';
        cout<<endl;
        if(i!=n-1) cout<<endl;
    }
    return 0;
}