C ++ addition of large numbers

# Include <iostream>
# Include <string>
# Include <stack>

Using namespace STD;

String add (string str1, string str2)
{
 // Operand 1
 Stack <int> S1;
 // Operand 2
 Stack <int> S2;
 // Result
 Stack <int> S3;

 Int I, R, last = 0;
 For (I = 0; I <str1.size (); I ++)
  S1.push (str1 [I]-'0 ');
 For (I = 0; I <str2.size (); I ++)
  S2.push (str2 [I]-'0 ');

while (! S1.empty ()&&! S2.empty ()
{< br> r = s1.top () + s2.top () + last;
s3.push (R % 10);
last = r/10;
s1.pop ();
s2.pop ();
}

If (! S1.empty ()
{< br> while (! S1.empty ()
{< br> r = s1.top () + last;
s3.push (R % 10);
last = r/10;
s1.pop ();
}< br> else if (! S2.empty ()
{< br> while (! S2.empty ()
{< br> r = s2.top () + last;
s3.push (R % 10);
last = r/10;
s2.pop ();
}

 If (last! = 0)
  S3.push (last );
 String result;
 While (! S3.empty ())
 {
  Result + = s3.top () + '0 ';
  S3.pop ();
 }

 Return result;
}

Int main (INT argc, char * argv [])
{
 Int I, N;
 Cin> N;
 String A, B;
 String * answer = new string [N];
 For (I = 0; I <n; I ++)
 {
  Cin> A> B;
  Answer [I] = add (A, B );
 }

for (I = 0; I {< br> cout }< br> Delete [] Answer;
return 0;
}< br>