Question

What kind of Loop Structure is this? Step Statement Notes iterations evals 8 iteration-8 9 evals-0 print( "Boolean evaluation #:", evals) print( "Iteration #: .., iteration) 2 2 while True: 4 5 print("Incurrent value of a:, a) iteration1 print( "Iteration #:", iteration) evals +1 print( "Boolean evaluation #:", evals) 7 8 9 10 ifa <-1: 5 print( InFinal value of a:"a) print("InTotal iterations:", iteration) print("Total Boolean evaluations:", evals) 12 13

Answer 1

The loop structure provided in the code is the while loop. The while loop is a control structure, which is used to execute a set of commands continuously by means of a Boolean (true or false) or Flag (1 or 0) input condition.  

STEP	STATEMENT	NOTES	a	iteration	evals
1	a=7 iteration = 0 evals = 0	The value of 'a' is initialized to be 7. The value of 'iteration' is initialized to be 0. The value of 'evals' is initialized to be 0.	7	0	0
2	print("Boolean evaluation #:", evals) print("Iteration #:", iteration)	'Boolean evaluation #: 0' is displayed. 'Iteration #: 0' is displayed.	7	0	0
3	while True :	The loop iterates as long as the value of 'a' holds true for 7.	7	0	0
4	a-=2	The value of 'a' is decremented by 2.	5	0	0
5	print("\nCurrent value of a:", a)	'Current value of a: 5' is displayed in the next line of the output.	5	0	0
6	iteration+=1	Increment the value of 'iteration' by 1.	5	1	0
7	print("Iteration #:", iteration)	'Iteration #: 1' is displayed.	5	1	0
8	evals+=1	Increment the value of 'evals' by 1.	5	1	1
9	print("Boolean evaluation #:", evals)	'Boolean evaluation #: 1' is displayed.	5	1	1
10	if a<=1 : break	Checks if the value of a is less than or equal to 1. Since, it is not satisfying the condition, it doesn't enter the if loop and iterates again.	5	1	1
11	a-=2	The value of 'a' is decremented by 2.	3	1	1
12	print("\nCurrent value of a:", a)	'Current value of a: 3' is displayed in the next line of the output.	3	1	1
13	iteration+=1	Increment the value of 'iteration' by 1.	3	2	1
14	print("Iteration #:", iteration)	'Iteration #: 2' is displayed.	3	2	1
15	evals+=1	Increment the value of 'evals' by 1.	3	2	2
16	print("Boolean evaluation #:", evals)	'Boolean evaluation #: 2' is displayed.	3	2	2
17	if a<=1 : break	Checks if the value of a is less than or equal to 1. Since, it is not satisfying the condition, it doesn't enter the if loop and iterates again.	3	2	2
18	a-=2	The value of 'a' is decremented by 2.	1	2	2
19	print("\nCurrent value of a:", a)	'Current value of a: 1' is displayed in the next line of the output.	1	2	2
20	iteration+=1	Increment the value of 'iteration' by 1.	1	3	2
21	print("Iteration #:", iteration)	'Iteration #: 3' is displayed.	1	3	2
22	evals+=1	Increment the value of 'evals' by 1.	1	3	3
23	print("Boolean evaluation #:", evals)	'Boolean evaluation #: 3' is displayed.	1	3	3
24	if a<=1 : break	Checks if the value of a is less than or equal to 1. Since, it is satisfying the condition, it enters the if loop and breaks the while loop.	1	3	3
25	print("\nFinal value of a:", a) print("\nTotal iterations :", iteration) print("\nTotal boolean evaluations:", evals)	'Final value of a: 1' is displayed in the next line of the output. 'Total iterations : 3' is displayed in the next line of the output. 'Total boolean evaluations: 3' is displayedi n the next line of the output.	1	3	3

A few print statements have been combined into a single step for ease of understanding. The above table depicts the execution steps, their explanations and the values of attributes declared of the code snippet provided in the question.