common_letter.gs

init
    // get args, declare variables

    first:string = args[1]
    second:string = args[2]
    common:bool = false
    first_pos:int = 0
    second_pos:int = 0

    first_length:long = first.length - 1
    second_length:long = second.length - 1

    var first_list = new array of char[first_length]
    var second_list = new array of char[second_length]

    for var i = 0 to first_length
        first_list[i] = (first[i])

    for var i = 0 to second_length
        second_list[i] = (second[i])

    // compare the words (gets the very first instance of the same char)

    for var i = 0 to first_length
        if common
            break
        second_pos = 0
        first_pos++

        for var j = 0 to second_length
            second_pos++
            if first_list[i] == second_list[j]
                common = true
                break

    // print values
    if common
        var first_final = (string)first_list
        var second_final = (string)second_list

        print first_final.substring(0, first_pos) + second_final.substring(second_pos) + "-" + second_final.substring(0, second_pos) + first_final.substring(first_pos)
    else
        print first + "-" + second