Conditional and Looping Constructs

Both A and R are true and R is the correct explanation of A.

Explanation
A compound statement in Python is formed when multiple statements are grouped together under the same block of indentation. The header line begins with a keyword and ends with a colon (:). Subsequent statements that are indented under the same level are considered part of the block.

Both A and R are true and R is the correct explanation of A.

Explanation
The if statement in Python allows conditional flow of control. It evaluates a condition and executes one or more statements based on whether the condition is true or false. If the condition evaluates to true, the statement block following the if statement (indented code) gets executed, otherwise, if the condition is false, that block is skipped, and the program continues with the next statement after the if block.

A is true but R is false.

Explanation
In an if-else statement, the if block checks the condition for the true part, whereas the else block executes if the condition is false. The else block in an if-else statement is not mandatory.

A is true but R is false.

Explanation
When a Python code is unable to accept an input, it results in a runtime error. Runtime errors arise due to issues that occur while the program is running, such as attempting to use invalid operations on data types. In contrast, syntax error arises due to incorrect statement that results in no output.

Both A and R are true and R is the correct explanation of A.

Explanation
In Python, break and continue are categorized as jump statements because they alter the flow of control in loops. Jump statements, such as break and continue, are used within loop constructs to control the flow of execution. Python does not have a switch-case conditional construct. Hence, in Python, jump statements are not used with conditional constructs.

A is false but R is true.

Explanation
The range() function is used with for loops to iterate over a sequence of numbers, not with while loops. By default, the values for start and step are 0 (zero) and 1 (one), respectively.

A is true but R is false.

Explanation
The for loop is described as a finite loop because it iterates over a sequence of elements with a known length. The while loop is described as an indefinite iterative construct because it continues to execute as long as a condition is true, without a predetermined number of iterations. We can use a while loop for menu-driven programs to repeatedly display a menu and process user input until a certain condition is met.

Flow chart

Reason — Flow chart is defined as a graphical representation of an algorithm to solve a given problem.

for statement

Reason — The for statement is not a decision-making statement in Python. Instead, the for loop statement is used to iterate/repeat itself over a range of values or a sequence.

Colon (:)

Reason — The symbol used to end the if statement is colon (:).

if

Reason — In Python, keywords are case-sensitive, meaning they must be written exactly as specified by the Python language. The valid keyword among the options provided is if.

101

Reason — In Python, if True: will always evaluate to True, so the code block under the if branch will execute.

do-while

Reason — In Python, the do-while loop statement does not exist. The language provides only two primary loop constructs: the for loop and the while loop, which are used to handle different looping requirements.

Infinite

Reason — The code will result in an infinite loop because the value of a is never modified within the loop. The condition a > 0 will always be true, causing the print(a) statement to be executed indefinitely without changing the value of a.

for

Reason — The for loop statement is used to iterate/repeat itself over a range of values or a sequence.

Directs the order of execution of the statements in the program

Reason — A control structure in a Python program is used to direct the order of execution of the statements in the program. Control structures, such as loops and conditional statements, determine the flow of control in the program, allowing for the execution of code blocks based on certain conditions or repeatedly based on a loop condition.

1,4,7,10,13,16,19,

Reason — The above code uses a for loop to iterate over a sequence of numbers generated by range(1, 20, 3). This range starts at 1, ends before 20, and increments by 3 in each step. During each iteration, the current value of x is printed followed by a comma due to the end=',' parameter in the print function. Therefore, the output is 1,4,7,10,13,16,19, showing the sequence of numbers separated by commas.

break

Reason — The break statement terminates the current loop, i.e., the loop in which it appears, and resumes execution at the next statement immediately after the end of that loop.

pass

Reason — The pass statement is an empty/null statement in Python that does nothing and acts as a dummy statement.

statements indented at a lower, same level

Reason — In Python, a block in a compound statement is created by indenting the statements to the same level.

A compound statement is a statement which comprises of a group of statements. The compound statements usually execute when a condition is satisfied, or a code block is called directly or through a function call.

Jump statements are used to unconditionally transfer program control to other parts within a program.

A loop may contain another loop as a part of its body. This loop inside a loop is called a nested loop. Once the condition of outer loop is true, the control is transferred to the inner loop. The inner loop is terminated first and then the outer loop terminates.

For example,

for i in range(1, 4):
    for j in range(1, i+1):
        print(j, end = '')
    print()

1
12
123

Here, range function will generate value 1, 2, 3 in the outer loop. The inner loop will run for each value of i used in outer loop. The value of outer loop variable will change only after the inner loop completely terminates.

Updating the loop control variable in while statements is essential to prevent infinite loops. If the loop control variable is not updated within the loop body, the condition may always evaluate to true, causing the loop to run indefinitely.

(a) (marks >= 100) and (marks < 70)

(b) (num > 0) and (num < 5) and (num != 2)

(c) (answer == 'N') or (answer == 'n')

(d) (age >= 18) and (gender == 'male')

(e) (city == 'Kolkata') or (city == 'Mumbai')

code = input("Enter season code : ")
if code=w: #Error 1
   print "winter season" #Error 2
elif code==r: #Error 3
   PRINT "rainy season" #Error 4 
else:
   Print "summer season" # Error 5

Error 1 — The assignment operator '=' is used instead of equality operator '==' in the if statement and the string 'w' should be enclosed in quotes.

Error 2 — Parentheses around the print statement are missing.

Error 3 — String 'r' should be enclosed in quotes.

Error 4 — The print statement should be in lowercase letters and there should be parentheses around the print statement.

Error 5 — The print statement should be in lowercase letters and there should be parentheses around the print statement.

The corrected code is :

code = input("Enter season code: ")
if code == "w":
   print("winter season") 
elif code == "r":  
   print("rainy season") 
else:
   print("summer season")  

guru99 1
guru99 2
guru99 3

The for loop iterates over each character in the string '123'. For each character, it prints "guru99" followed by the character. The comma after i in the print() function ensures a space between "guru99" and each character.

100
200
300

The above code iterates through each element in the list [100, 200, 300] using a for loop. During each iteration, it prints the current element i.

20
16

1. range(10, 6, -2): This generates a sequence of numbers starting from 10 (inclusive) and decreases by 2 each time, stopping before it reaches 6 (exclusive).

The general form of the range function is range(start, stop, step), where:

• start is the starting number of the sequence.
• stop is the endpoint (the number is not included in the sequence).
• step specifies the increment (or decrement, if negative) between each number in the sequence.

2. The sequence generated by range(10, 6, -2) is:

• Start at 10.
• Decrement by 2: 10 - 2 = 8.
• The next decrement would be 8 - 2 = 6, but 6 is not included as it is exclusive.

So, the sequence generated is: 10, 8.

3. for j in range(10, 6, -2):: The for loop iterates over each number in the sequence generated by the range function.

4. print(j * 2): This prints the value of j multiplied by 2 for each iteration.

Let’s analyze the loop iteration by iteration:

First iteration (j = 10):

print(10 * 2)

This prints:

20

Second iteration (j = 8):

print(8 * 2)

This prints:

16

Putting it all together, the full output will be:

20
16

1   1
2   1
2   2
3   1
3   2
3   3
4   1
4   2
4   3
4   4
5   1
5   2
5   3
5   4
5   5

Below is the detailed explanation of this code:

1. Outer Loop: for x in range(1, 6):

• This loop iterates over the range of numbers starting from 1 up to but not including 6. So, x will take on the values: 1, 2, 3, 4, 5.

2. Inner Loop: for y in range(1, x + 1):

• For each value of x in the outer loop, y will iterate over the range of numbers starting from 1 up to and including x (since x + 1 is exclusive).

3. print(x, ' ', y)

• This prints the current values of x and y separated by a space.

Let’s analyze the loops iteration by iteration.

Outer loop (x values ranging from 1 to 5):

When x = 1:

• The inner loop range(1, 2) results in y taking values: 1.
• Output:

  1   1
  

When x = 2:

• The inner loop range(1, 3) results in y taking values: 1, 2.
• Output:

  2   1
  2   2
  

When x = 3:

• The inner loop range(1, 4) results in y taking values: 1, 2, 3.
• Output:

  3   1
  3   2
  3   3
  

When x = 4:

• The inner loop range(1, 5) results in y taking values: 1, 2, 3, 4.
• Output:

  4   1
  4   2
  4   3
  4   4
  

When x = 5:

• The inner loop range(1, 6) results in y taking values: 1, 2, 3, 4, 5.
• Output:

  5   1
  5   2
  5   3
  5   4
  5   5
  

Putting all these outputs together, we get:

1   1
2   1
2   2
3   1
3   2
3   3
4   1
4   2
4   3
4   4
5   1
5   2
5   3
5   4
5   5

10
11
12
13
14

The code starts a for loop where x iterates over the range from 10 to 19. Within each iteration, it checks if x is equal to 15. If true, the break statement exits the loop. Therefore, the loop prints numbers from 10 to 14, each on a new line.

11
13
15
17
19

Below is the detailed explanation of this code:

1. for x in range(10, 20): → This loop iterates over the range of numbers starting from 10 (inclusive) up to but not including 20 (exclusive). So, x will take on the values: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19.

2. if x % 2 == 0: → For each value of x, this condition checks if x is an even number. The modulus operator % returns the remainder of x divided by 2. If the remainder is 0, x is even.

3. continue → If the condition x % 2 == 0 is true (i.e., x is even), the continue statement is executed. This statement skips the rest of the code inside the loop for the current iteration and moves to the next iteration.

4. print(x) → This line prints the value of x if it is not even (i.e., if the continue statement is not executed).

Let’s analyze the loop iteration by iteration:

• When x = 10:

  • 10 % 2 == 0 is true.
  • continue is executed, so print(x) is skipped.

• When x = 11:

  • 11 % 2 == 0 is false.
  • print(x) outputs:

    11
    

• When x = 12:

  • 12 % 2 == 0 is true.
  • continue is executed, so print(x) is skipped.

• When x = 13:

  • 13 % 2 == 0 is false.
  • print(x) outputs:

    13
    

• When x = 14:

  • 14 % 2 == 0 is true.
  • continue is executed, so print(x) is skipped.

• When x = 15:

  • 15 % 2 == 0 is false.
  • print(x) outputs:

    15
    

• When x = 16:

  • 16 % 2 == 0 is true.
  • continue is executed, so print(x) is skipped.

• When x = 17:

  • 17 % 2 == 0 is false.
  • print(x) outputs:

    17
    

• When x = 18:

  • 18 % 2 == 0 is true.
  • continue is executed, so print(x) is skipped.

• When x = 19:

  • 19 % 2 == 0 is false.
  • print(x) outputs:

    19
    

Putting all these outputs together, the full output will be:

11
13
15
17
19

ok
average

1. if x > 10:

   • The condition checks if x is greater than 10.
   • Since x = 50, which is greater than 10, this condition is true.

2. Nested if x > 25:

   • Since the outer condition is true, the program proceeds to this nested condition, which checks if x is greater than 25.
   • Since x = 50, which is greater than 25, this condition is also true.
   • Consequently, it prints ok

3. Nested if x > 60:

   • After printing 'ok', the program checks this nested condition, which verifies if x is greater than 60.
   • Since x = 50, which is not greater than 60, this condition is false.
   • Therefore, the program proceeds to the elif part.

4. Nested elif x > 40:

   • This condition checks if x is greater than 40.
   • Since x = 50, which is greater than 40, this condition is true.
   • Consequently, it prints average

5. The else block

   • The else block is not executed because the elif x > 40: condition was true.

o o

Let’s break down the code step-by-step:

1. Outer Loop: for i in range(2): → This loop iterates over the range of numbers starting from 0 up to but not including 2. So, i will take on the values: 0, 1.

2. Inner Loop: for j in range(1): → For each value of i in the outer loop, j will iterate over the range of numbers starting from 0 up to but not including 1. So, j will take on the only value: 0.

3. if i + 2 == j: → This condition checks if i + 2 is equal to j.

4. print("+", end=" ") → If the condition i + 2 == j is true, this statement prints a "+", followed by a space, without moving to a new line.

5. print("o", end=" ") → If the condition i + 2 == j is false, this statement prints an "o", followed by a space, without moving to a new line.

Let’s analyze the loops iteration by iteration:

• First iteration of the outer loop (i = 0):
  • Inner loop (j = 0):
    • i + 2 == j becomes 0 + 2 == 0, which is 2 == 0, is false.
    • Therefore, the else block is executed, and the output is o
• Second iteration of the outer loop (i = 1):
  • Inner loop (j = 0):
    • i + 2 == j becomes 1 + 2 == 0, which is 3 == 0, is false.
    • Therefore, the else block is executed, and the output is o

So, combining the outputs of all iterations, the full output will be:

o o 

Each "o" is followed by a space, and there is no new line between them due to the end=" " parameter in the print function.

9

In the above code, num1 += num2 + num3 is a shorthand notation for num1 = num1 + num2 + num3.

Given,

num1 = 4
num2 = 3
num3 = 2

First, the expression num2 + num3 is evaluated:

num2 + num3 = 3 + 2 = 5

Now the expression becomes:

num1 = num1 + 5

which translates to:

num1 = 4 + 5 = 9

1024

In the given code, num1 = num1 ** (num2 + num3) calculates the result of raising num1 to the power of the sum of num2 and num3. The expression becomes 4 ** (3 + 2), which simplifies to 4 ** 5. Evaluating 4 ** 5 results in 1024, so the output of print(num1) is 1024.

There is an error in the given code because the variable c is not defined. This will raise a NameError at runtime.

55

The expression '5' + '5' performs string concatenation as they are enclosed in quotes. Therefore, '5' and '5' are concatenated to form the string '55', which is then assigned to num1. The print(num1) statement outputs the string '55'.

1.0

1. Evaluate the expression inside the parentheses first:

2.0 + 2.0

This calculation is straightforward:

2.0 + 2.0 = 4.0

2. Perform the division operation:

4.00 / 4.0 = 1.0

3. Print the result:

print(1.0)

Therefore, the output of the given code snippet is:

1.0

27.2

num1 = 2 + 9 * ((3*12)-8)/10

Let's calculate this step by step, following the precedence of operators in Python:

1. Evaluate the innermost parentheses first:

3 * 12 = 36

2. Replace and continue evaluating inside the parentheses:

((3*12)-8) => (36 - 8) = 28

3. Now, evaluate the multiplication and division:

9 * 28 = 252

4. Continue with dividing by 10:

252 / 10 = 25.2

5. Finally, add 2:

2 + 25.2 = 27.2

The print(num1) statement outputs 27.2

10.0

The float(10) function converts the integer 10 to the floating-point number 10.0. Therefore, num1 is assigned the value 10.0.

3

The expression float('3.14') converts the string '3.14' to the floating-point number 3.14. The int() function then converts 3.14 to the integer 3 by truncating the decimal part. Thus, num1 is assigned the value 3, and print(num1) outputs 3.

True

The expression 10 != 9 and 20 >= 20 evaluates to True because both conditions separated by the and operator are true. Specifically, 10 != 9 is true because 10 is not equal to 9, and 20 >= 20 is true because 20 is equal to 20.

True

In the expression 5 % 10 + 10 < 50 and 29 <= 29, according to operator precedence, 5 % 10 calculates to 5, then 5 + 10 equals 15. Next, 15 < 50 evaluates to True. Separately, 29 <= 29 also evaluates to True. The and operator then combines these results. Since both conditions are True, the and operator yields True, which is printed.

The else statement is a default condition that executes when the preceding if and elif (if any) conditions evaluate to False. It does not take any conditions and is written simply as else:, followed by an indented block of code. On the other hand, elif is used to check additional conditions after the initial if statement. If the if condition is False, Python evaluates the elif condition. It is followed by a condition and ends with a colon (:), followed by a block of code.

20
22
24
26
28

Below is a detailed explanation of this code:

1. range(20, 30, 2): This generates a sequence of numbers starting from 20 (inclusive) up to but not including 30 (exclusive), incrementing by 2 each time.
   The general form of the range function is range(start, stop, step),where:

   • start is the starting number of the sequence.
   • stop is the endpoint (the number is not included in the sequence).
   • step specifies the increment between each number in the sequence.

2. for i in range(20, 30, 2):: The for loop iterates over each number generated by the range function and assigns it to the variable i during each iteration.

3. print(i): This prints the current value of i for each iteration.

Let's list the numbers generated by range(20, 30, 2):

• Start at 20.
• Increment by 2: 20 + 2 = 22.
• Increment by 2: 22 + 2 = 24.
• Increment by 2: 24 + 2 = 26.
• Increment by 2: 26 + 2 = 28.
• The next increment would be 28 + 2 = 30, but 30 is not included as the stop parameter is exclusive of the value.

Therefore, the sequence of numbers is: 20, 22, 24, 26, 28.

I
N
D
I
A

Here's the detailed explanation:

1. String Assignment:

country = 'INDIA'

This line assigns the string 'INDIA' to the variable country.

2. for i in country:: The for loop iterates over each character in the string country. The variable i will take on the value of each character in the string one at a time.

3. print(i): This prints the current character stored in the variable i for each iteration.

Let’s analyze the loop iteration by iteration:

• In the first iteration, i is 'I', so print(i) outputs: I.
• In the second iteration, i is 'N', so print(i) outputs: N.
• In the third iteration, i is 'D', so print(i) outputs: D.
• In the fourth iteration, i is 'I', so print(i) outputs: I.
• In the fifth iteration, i is 'A', so print(i) outputs: A.

Putting it all together, the output will be each character of the string 'INDIA' printed on a new line:

I
N
D
I
A

12

Let's break down the code step-by-step:

1. Initial Assignments:

i = 0
sum = 0

Two variables are initialized: i is set to 0, and sum is set to 0.

2. while i < 9: → This loop continues to execute as long as i is less than 9.

3. Inside the while loop:

• First iteration (i = 0):

  • if i % 4 == 0: → 0 % 4 equals 0, so the condition is true.
  • sum = sum + i → sum is updated to sum + 0, which is 0 + 0 = 0.
  • i = i + 2 → i is updated to 0 + 2 = 2.

• Second iteration (i = 2):

  • if i % 4 == 0: → 2 % 4 equals 2, so the condition is false.
  • The value of sum remains unchanged.
  • i = i + 2 → i is updated to 2 + 2 = 4.

• Third iteration (i = 4):

  • if i % 4 == 0: → 4 % 4 equals 0, so the condition is true.
  • sum = sum + i → sum is updated to sum + 4, which is 0 + 4 = 4.
  • i = i + 2 → i is updated to 4 + 2 = 6.

• Fourth iteration (i = 6):

  • if i % 4 == 0: → 6 % 4 equals 2, so the condition is false.
  • The value of sum remains unchanged.
  • i = i + 2 → i is updated to 6 + 2 = 8.

• Fifth iteration (i = 8):

  • if i % 4 == 0: → 8 % 4 equals 0, so the condition is true.
  • sum = sum + i → sum is updated to sum + 8, which is 4 + 8 = 12.
  • i = i + 2 → i is updated to 8 + 2 = 10.

• Sixth iteration (i = 10):

  • The loop condition while i < 9: is no longer true (10 is not less than 9), so the loop terminates.

4. print(sum) → After exiting the loop, the value of sum is printed.

Summarizing all updates to sum:

• After the first iteration, sum = 0.
• After the third iteration, sum = 4.
• After the fifth iteration, sum = 12.

Therefore, the output of the code is:

12

False

Reason — Flow chart is the pictorial representation of step-by-step solution to a given problem.

False

Reason — The if, elif, and else are block or compound statements in Python.

True

Reason — In Python, every compound statement has a header and indented body below the header.

True

Reason — In Python, a block is a group of consecutive statements that are intended to be executed together under a certain condition or scope.

True

Reason — The pass statement serves as a placeholder in Python. It is an empty statement that does nothing and acts as a dummy statement.

True

Reason — To cancel the running of endless loop, we can press CTRL+ C key any time during its endless repetition to stop it.

False

Reason — In Python, indentation is necessary to define a block of code within control structures such as if, for, and while statements, as well as within functions.

False

Reason — Python does not have an else if statement. Instead, Python uses the elif statement to chain multiple conditional statements together.

True

Reason — The continue statement in Python is used within loops to skip the rest of the code inside the current iteration and immediately proceed to the next iteration of the loop.

True

Reason — In Python, the else block associated with a for loop is executed when the loop terminates normally, meaning it has iterated over all items or reached its termination condition.

True

Reason — Iteration refers to the process of repeatedly executing a set of statements or a block of code for a specified number of times.