Question 1

Question 1Consider the following code fragment :while
    n = 3
    print n == 3(a) What will be the output of above code ?(b) What is the reason behind this output ?

Accepted Answer

(a) The given code will generate a syntax error.(b) The condition of while and colon after that is missing. Thus a syntax error is generated.

Question 2

Question 2Consider the following code fragment :n = 3
while n == 3
    print n
n = n - 1(a) What will be the output of above code?(b) What is the reason behind this output ?(c) What change/corrections will you make to above code to make it print some output ?

Accepted Answer

(a) The given code will generate a syntax error.(b) The syntax of while statement has a colon after the condition which is missing in the given code. Thus, a syntax error is generated.(c) The following changes must be made to the code to print some output:n = 3
while n == 3 :
    print (n)
    n = n - 1The code given above will generate the following output:3

Question 3

Question 1Which of the following are invalid conditional statements of Python?IFTest ifif-elseif-elififif-elif-else

Accepted Answer

IF and Test ifReason — IF and Test if are invalid conditional statements of Python.

Question 4

Question 2Which of the following is/are not a valid Python loop ?forwhileiterrepeat

Accepted Answer

iter, repeatReason — iter and repeat are not valid Python loop. for and while are valid loop statements.

Question 5

Question 3Which of the following is used to define a block of code (e.g., body of if or body of a loop) in Python ?{ }( )indentationQuotation

Accepted Answer

indentationReason — Indentation is used to define a block of code in Python.

Question 6

Question 4What is the output of following code ?if None :
    print "Up"
else:   
    print "Down"UpDownNo outputUp Down

Accepted Answer

DownReason — Since None is treated as false, the if condition results in false. The block of if will be ignored and the else block will be executed and Down will be printed on the output screen.

Question 7

Question 5What will be the output of following code ?for i in range(1) : 
    print i01No outputError in code

Accepted Answer

0Reason — The range(n) function generates a list as [0, 1, 2..., n - 1]. Thus, the range(1) function will generate a list as [0]. Thus the for loop will execute only one time and print 0 on the output terminal.

Question 8

Question 6What will the output of following code ?for i in range(1, 0) :
    print i01No outputError in code

Accepted Answer

No outputReason — The function range(1, 0) will return return an empty list [] as no number falls in the arithmetic progression beginning with 1 and ending with 0. Thus, the for loop will not execute even once and hence, no output will be generated on the output screen.

Question 9

Question 7What is the output of following code ?while 3 >= 3 :
    print 33 is printed once3 is printed three times3 is printed infinitely until program is closedError in code

Accepted Answer

3 is printed infinitely until program is closedReason — Since the given condition (3 >= 3) will always remain true, the while loop will execute indefinitely and keep on printing 3 on the output screen till the program is closed.

Question 10

Question 1What are selection statements ? How are they useful ?

Accepted Answer

A statement that carries out a set of instructions depending upon a condition's result is known as a selection or conditional statement. Python provides selection statements in the form of if and if-else statements.These statements enable a program to carry out a set of instructions depending upon a condition's result. For example,num = 5
if num >= 0 :
    print "Positive"
else :
    print "Negative"

Question 11

Question 2What are looping statements ? How are they useful ?

Accepted Answer

A statement that allows a set of instructions to be performed repeatedly is known as a looping or iteration statement. Python provides looping statements in the form of for and while loop.These statements enable a program to perform a set of instructions repeatedly. For example,num = 3
while num > 0 :
    print num
    num = num - 1

Question 12

Question 3Differentiate between if and if-else statements.

Accepted Answer

Difference between if and if-else statements in Python:S.No.ifif-else1.if statement allows us to execute a code block when the condition is True.if-else statement allows us to execute different code blocks based on whether the condition is True or False.2.if statement does nothing in case condition evaluates to False.if-else statement executes the statements indented below else when the condition is False.

Question 13

Question 4Differentiate between for and while statements.

Accepted Answer

Difference between for and while statements in Python:S.No.forwhile1.for loop is used when the number of iterations are known beforehand.while loop is used when the number of iterations are not fixed and depends on a specific condition.2.for loop is used for iterating over a sequence or a range.while loop is used for repeated execution based on a condition.3.Syntax:for in : statements_to_repeatSyntax:while : statements_to_repeat

Question 14

Question 5(a)Rewrite the following code fragments using for loopwhile num > 0 :
    print num % 10 
    num = num/10

Accepted Answer

l = [1]
for x in l:
    l.append(x + 1)
    if num <= 0:
        break
    print (num % 10)
    num = num/10

Question 15

Question 5(b)Rewrite the following code fragments using for loopi = 100
while (i > 0) :
    print i
    i -= 3

Accepted Answer

for i in range(100, 0, -3) :
    print (i)

Question 16

Question 6What is following code doing ? What would it print for input as 3 ?n = input( "Enter an integer:" )
if n < 1 :
    print "invalid value"
else :
    for i in range(1, n + 1): 
        print i * i

Accepted Answer

The code will print the square of each number from 1 till the number given as input by the user if the input value is greater than 0. Output of the code for input as 3 is shown below:Enter an integer:3
1
4
9

Question 17

Question 7(a)Rewrite following code fragments using while loopsmin = 0 
max = num 
if num < 0 :
    min = num 
    max = 0 
# compute sum of integers from min to max 
for i in range(min, max + 1): 
    sum += i

Accepted Answer

min = 0
max = num
if num < 0 :
    min = num
    max = 0
# compute sum of integers from min to max 
i = min
while i <= max:
    sum += i
    i += 1

Question 18

Question 7(b)Rewrite following code fragments using while loopsfor i in range(1, 16) : 
    if i % 3 == 0 : 
        print i

Accepted Answer

i = 1
while i < 16:
    if i % 3 == 0 :
        print (i)
    i += 1

Question 19

Question 8(i)Write a short program to print the following series :1 4 7 10 ........... 40.

Accepted Answer

Solutionfor i in range(1, 41, 3) :
    print(i, end = ' ')Output1 4 7 10 13 16 19 22 25 28 31 34 37 40

Question 20

Question 8(ii)Write a short program to print the following series :1 -4 7 -10 .......... -40

Accepted Answer

Solutionx = 1
for i in range(1, 41, 3) :
    print(i * x, end = ' ')
    x *= -1Output1 -4 7 -10 13 -16 19 -22 25 -28 31 -34 37 -40

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