A + B Problem II

#include<iostream>
#include<cstring>
using namespace std;
void add(char s1[],char s2[])
{
    int i,j,k;
    int a[1010],b[1010],len1,len2;
    memset(a,0,sizeof(a));
    memset(b,0,sizeof(b));
    len1=strlen(s1);
    len2=strlen(s2);
    j=0;
    for(i=len1-1;i>=0;i--)
        a[j++]=s1[i]-‘0‘;
        k=0;
    for(i=len2-1;i>=0;i--)
        b[k++]=s2[i]-‘0‘;
    for(i=0;i<1010;i++)
    {    a[i]+=b[i];
        if(a[i]>=10)
        {
            a[i]-=10;
            a[i+1]++;
        }
    }
    for(i=1005;i>=0;i--)
    {
        if(a[i]) break;
    }
    for( ;i>=0;i--)
    cout<<a[i];
}
int main()
{
    int i;
    char c[1010];
    char d[1010];
    int n;
    cin>>n;
    for(i=1;i<=n;i++)
    {
         cin>>c>>d;
         cout<<"Case "<<i<<":"<<endl;
         cout<<c<<" +"<<‘ ‘<<d<<" ="<<‘ ‘;
         add(c,d);
         cout<<endl;
         if(i!=n)
         cout<<endl;
    }
    return 0;
}