UVA-713-Adding Reversed Number

#include<iostream>
#include<string>
#include<cstring>

using namespace std;



string reverse(string a){
                    int i,j;
                    string b="";
                    for(j=a.length()-1;j>=0;j--)
                        b+=a[j];
                    return b;
                    }
string add(string n1, string n2){
                                int i,j,x,y,sum,s;
                                string result="";
                                string a,b,final_result;
                                int carry=0;
                                a=rev(n1);
                                b=rev(n2);
                                for(i=0;i<a.length();i++)
                                    {
                                    if(i<b.length())
                                            {
                                            x=a[i]-'0';
                                            y=b[i]-'0';
                                            sum=x+y+carry;
                                            s=sum%10;
                                            result+=s+'0';
                                            carry=0;
                                            if(sum>9) carry=1;
                                            if(i==a.length()-1 && carry==1)
                                                result+='1';
                                            }
                                    else {
                                         x=a[i]-'0';
                                         sum=carry+x;
                                         s=sum%10;
                                         result+=s+'0';
                                         carry=0;
                                         if(sum>9) carry=1;
                                            if(i==a.length()-1 && carry==1)
                                                result+='1';
                                         }
                                    }
                                final_result=rev(result);
                                return final_result;
                                }

int main()
{
    int n;
    cin>>n;
    while(n--)
    {
        int zero=0,k=0,i;
        string num1, num2;
        cin>>num1>>num2;
        string result=rev(add(rev(num1),rev(num2)));


         for(i=0;i<=result.length()-1;i++)
         {
             if(result[i]=='0')
             zero++;
         }
         for(i=zero;i<result.length();i++)
         cout<<result[i];
         cout<<endl;

    }
    return 0;
}