''' Purpose: introduce nested looping.
        for a user-supplied n, loop n times where on the i-th iteration,
        the integers from 0 to i are printed out.
'''
import pause
# get integer of interest
reply = input( 'Enter number: ' )

n = int( reply )

# repeat n times
# output = ''  # if you initialize output here, you get a different output because of the way the loops are structured...play with it and see what happens
for row in range(0, n) :  # 3 things happen in this for loop: output gets initialized, the next for loop is initiated, and then output is printed
    # we want to output the numbers 0 through i
    # first output is 0, next one is 0 1, then 0 1 2, ..., and finally output 0 1 2 ... n-1
    # print(i) # not what we want...just outputs i
    output = ''  # this is an accumulator for the nested for loop below
    for column in range(0, row+1): # 0 to i INCLUDING i
        # print(j)  # this gets the output we want, but not on the same line...
        # output = output + j # by itself results in error TypeError: must be str, not int
        # convert j to a string
        js = str(column)
        output = output + js + " " # adds a space between the numbers
    print(output)  # play with the indentation of this line and see what happens...INDENTATION MATTERS
    # pause.enter_when_ready()
# n is the number of times we want work to be done; for this specific algorithm, it's the number of rows outputted

# we could probably do this code using a list and appending to it,
    # but if we want just a string output, using a list requires a little bit more hassle

print()
print("All done!")