import random

def a():
    sentinel = 0
    array = []
    while sentinel < 50:
        item = random.randrange(0, 21) 
        array.append(item)
        sentinel += 1
    print "50 numbers between 0 and 20:"
    print array

def b():
    sentinel = 0
    array = []
    while sentinel < 50:
        item = random.randrange(-10, 11)
        array.append(item)
        sentinel += 1
    print "50 numbers between -10 and 10:"
    print array

def c():
    sentinel = 0
    array = []
    while sentinel < 50:
        item = random.randrange(-100, 101)
        if item % 10 == 0:
            array.append(item)
            sentinel += 1
    print "50 numbers between -100 and 100, in steps of 10:"
    print array