funcaddStrings(num1 string, num2 string)string { carry := 0 result := "" for i, j := len(num1)-1, len(num2)-1; i >= 0 || j >= 0 || carry !=0; { var x, y int if i >= 0 { x += int(num1[i] - '0') } if j >= 0 { y += int(num2[j] - '0') } now := x + y + carry result = strconv.Itoa(now % 10) + result carry = now / 10 i-- j-- } return result }