print("\nPlaying with functions ...\n")

def diagnostic(test = 0, content = "diagnostic help"):
    '''Diagnostic is designed to print useful diagnostic information.
    The second var is the text to print, default is "diagnostic help".
    If the first var = 1 then print happens, otherwise not, default is 0'''
    if test == 1:
        print(">>>>\t" + content + "\t\t<<<<")


def get_int_from_keyboard( show = 0 ) :
    '''get_int_from_keyboard asks for an integer and returns the input as an integer.
    If bad input is given then it returns -999.
    Careful manual checking to see if the first character is a + or -
    The input var should be an integer which prints diagnostic info if set to 1, default 0'''
    print("please enter an integer\n")
    str_input = input( )
    diagnostic(show , "/t>>> you gave me " + str_input) ## diagnostic
    if str_input.isdigit():
        diagnostic(show , "it's a non-negative integer")
        return int(str_input) ## so it was a non-negative integer

    ## we only get here if we haven't already returned!!!
    if len(str_input) > 1:
        ## check to see if it's a negative integer by looking at the first character of the input string
        firstChar = str_input[0]
        minusPlus = False # a default value which might change
        if firstChar == '+' or firstChar == '-':
            minusPlus = True
        diagnostic(show , "it's not a +ve int, but it's longish and minusPlus = " +str(minusPlus))
        if minusPlus and str_input[1:].isdigit():
            diagnostic(show , "it's a pos or neg integer ... " + str_input)
            return int(str_input) ## so it was a negative integer
        diagnostic(show , "it's longish but isn't digity after the first character")

    ## it's neither a positive nor a negative integer :(
    print("OUCH -- you didn't give me what I wanted!!!! I'm going to return -999")
    return -999


print("\tabout to demonstrate how default values for functions work ...\n")
diagnostic(0,"IO")
diagnostic(1)
diagnostic(1, "goofy")

print("\n\tNow to get into the real program ...\n")

show = 0 ## this will hide the diagnostic printouts, set show = 1 to see them

compoundMe = get_int_from_keyboard(show) * get_int_from_keyboard(show)

print("\n\ttesting the function ... the product = " + str(compoundMe))