Programming question given to me at leetcode. Given two strings representing very large integer numbers ("123" , "30") return a string representing the sum of the two numbers ("153"). The above question can be rephrased as:- Add two numbers represented by strings Sum of two large numbers Add Two Very Large Number (out of range) How to add two string numbers Solution in Swift programming language: func add (first: String , second: String ) { var input1 = first var input2 = second var firstArray = Array (first) var secondArray = Array (second) //both inputs should have same number of characters var differenceOfCharacter = 0 if firstArray. count > secondArray. count { differenceOfCharacter = firstArray. count - secondArray. count ( 0 ..< differenceOfCharacter). forEach