Page 162 - Information_Practice_Fliipbook_Class11
P. 162
03 j = 1
04 print one *
05 print newline
06 i = 2
07 print 6-2=4 spaces
08 j = 1
09 print one *
10 j = 2
11 print one space
12 j = 3
13 print one *
14 print newline
15 i = 3
16 print 6-3=3 spaces
17 j = 1
18 print one *
19 j = 2
20 print one space
21 j = 3
22 print one space
23 j = 4
24 print one space
25 j = 5
26 print one *
27 print newline
28 and so on
6.8 Infinite Loop
A while loop becomes an infinite loop if the test condition never yields False. For example,
01 while True:
02 s = 1
03 print(s)
In the above code snippet, the test expression always yields True. But you may ask, why would anybody write a code
like the one above. Of course, no one would, except by an error. Next, consider the following code snippet. The code
aims to find the sum of positive numbers entered by a user. The control leaves the loop as soon as it encounters zero
or a negative number, and the sum of the positive numbers is printed.
01 sumNums = 0
02 num = int(input('enter a number: '))
03 while num>0:
04 sumNums = sumNums + num
05 num = int(input('enter a number: '))
06 print('Sum of all numbers: ', sumNums)
In the above code, we are required to include the code to input a number twice, whereas it is indeed part of the loop.
So, the following code that sets the Boolean expression in the while loop as True would be better:
01 sumNums = 0
02 while True:
03 num = int(input('enter a number: '))
04 if num>0:
05 sumNums = sumNums + num
06 else:
07 break
08 print('Sum of all numbers: ', sumNums)
148 Touchpad Informatics Practices-XI

