Pseudocode for planning in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Pseudocode Purpose

What is the main purpose of writing pseudocode before coding?

A To plan the steps of a program in simple language without worrying about syntax

B To create a detailed, executable program that runs on a computer

C To write the final version of the program in a specific programming language

D To test the program's performance and speed

💡 Hint

Think about how pseudocode helps programmers think through problems.

Pseudocode is used to plan the logic of a program in plain language. It helps programmers organize their thoughts before writing actual code.

❓ trace

intermediate

Tracing Pseudocode Execution

Given the following pseudocode, what will be the final value of total?

SET total TO 0
FOR each number FROM 1 TO 4
  ADD number TO total
END FOR

A 10

B 24

C 4

D 0

💡 Hint

Sum the numbers 1 + 2 + 3 + 4 step by step.

The loop adds 1 + 2 + 3 + 4 to total, which equals 10.

❓ Comparison

advanced

Comparing Pseudocode and Flowchart

Which statement best describes the difference between pseudocode and a flowchart?

A Flowcharts are faster to write than pseudocode.

B Pseudocode uses pictures to show steps; flowcharts use words only.

C Pseudocode is written in plain text; flowcharts use symbols and arrows to show flow.

D Flowcharts are only used for hardware design; pseudocode is for software.

💡 Hint

Think about how each method represents the steps of a program.

Pseudocode is text-based and describes steps in words. Flowcharts use shapes and arrows to visually represent the flow of steps.

❓ identification

advanced

Identifying Errors in Pseudocode

Which option shows pseudocode with a logical error?

Option A:
SET count TO 5
WHILE count > 0
  PRINT count
  DECREMENT count BY 1
END WHILE

Option B:
SET count TO 0
WHILE count < 5
  PRINT count
END WHILE

Option C:
SET total TO 0
FOR i FROM 1 TO 3
  ADD i TO total
END FOR

Option D:
SET x TO 10
IF x > 5 THEN
  PRINT "High"
END IF

A Option A has a logical error because it never stops.

B Option D has a logical error because the condition is always false.

C Option C has a logical error because the loop runs backwards.

D Option B has a logical error because count is never changed inside the loop.

💡 Hint

Look for loops that might never end.

Option D's loop never changes count, so it runs forever, causing an infinite loop.

🚀 Application

expert

Planning with Pseudocode for a Real-World Task

You want to write pseudocode to plan a program that checks if a number is prime. Which pseudocode snippet correctly plans this task?

A

SET number TO input
FOR i FROM 2 TO number
  IF number MOD i EQUALS 0 THEN
    PRINT "Prime"
  ELSE
    PRINT "Not prime"
  END IF
END FOR

B

SET number TO input
FOR i FROM 2 TO number-1
  IF number MOD i EQUALS 0 THEN
    PRINT "Not prime"
    STOP
  END IF
END FOR
PRINT "Prime"

C

SET number TO input
IF number MOD 2 EQUALS 0 THEN
  PRINT "Prime"
ELSE
  PRINT "Not prime"
END IF

D

SET number TO input
FOR i FROM 1 TO number
  PRINT i
END FOR
PRINT "Prime check complete"

💡 Hint

Think about how to test divisibility to confirm if a number is prime.

Option B correctly checks divisibility from 2 up to number-1 and stops if a divisor is found, printing "Not prime"; otherwise, it prints "Prime".

Practice

1. What is the main purpose of writing pseudocode before programming?

easy

A. To design the colors and layout of a website

B. To write the exact code that runs on a computer

C. To plan the steps of a program in simple language

D. To test the program for errors automatically

Solution

1. Step 1: Understand what pseudocode is

   Pseudocode is a way to write down the steps of a program using plain words, not actual code.

2. Step 2: Identify the purpose of pseudocode

   It helps programmers plan and think through the logic before writing real code.

3. Final Answer:

   To plan the steps of a program in simple language -> Option C

4. Quick Check:

   Pseudocode = Plan steps [OK]

Hint: Pseudocode is like a recipe for your program [OK]

Common Mistakes:

• Confusing pseudocode with actual code
• Thinking pseudocode runs on computers
• Mixing design tasks with pseudocode purpose

2. Which of the following is the correct way to write an IF statement in pseudocode?

easy

A. IF temperature > 30 THEN
print "Hot"
END IF

B. if temperature > 30 {
print("Hot")
}

C. IF temperature > 30:
print("Hot")

D. if (temperature > 30) print "Hot"

Solution

1. Step 1: Identify pseudocode style

   Pseudocode uses simple keywords like IF, THEN, and END IF with indentation to show logic.

2. Step 2: Compare options

   IF temperature > 30 THEN print "Hot" END IF uses uppercase keywords and END IF, which is typical for pseudocode. Others use programming syntax.

3. Final Answer:

   IF temperature > 30 THEN print "Hot" END IF -> Option A

4. Quick Check:

   IF ... THEN ... END IF is pseudocode style [OK]

Hint: Look for uppercase keywords and END IF in pseudocode [OK]

Common Mistakes:

• Using programming language syntax instead of pseudocode
• Missing END IF to close the IF block
• Not using THEN after IF condition

3. Consider this pseudocode:

SET total TO 0
FOR i FROM 1 TO 3
    total = total + i
END FOR
PRINT total

What will be the output?

medium

A. 0

B. 6

C. 3

D. Error

Solution

1. Step 1: Trace the FOR loop iterations

   The loop runs with i = 1, 2, 3. Each time, total adds i: 0+1=1, 1+2=3, 3+3=6.

2. Step 2: Determine the final value of total

   After the loop, total is 6, which is printed.

3. Final Answer:

   6 -> Option B

4. Quick Check:

   Sum 1+2+3 = 6 [OK]

Hint: Add numbers 1 to 3 step-by-step [OK]

Common Mistakes:

• Stopping loop early and getting 3
• Forgetting to add inside the loop
• Confusing pseudocode with syntax errors

4. This pseudocode has an error:

SET count TO 0
FOR i FROM 1 TO 5
count = count + 1
PRINT count
END FOR

What is the error?

medium

A. FOR loop is missing END FOR

B. Variable i is not used

C. count should start at 1, not 0

D. PRINT is inside the loop but not indented

Solution

1. Step 1: Check indentation for loop body

   In pseudocode, statements inside loops must be indented to show they belong to the loop.

2. Step 2: Identify the misplaced PRINT statement

   PRINT count is not indented, so it looks outside the loop, causing confusion.

3. Final Answer:

   PRINT is inside the loop but not indented -> Option D

4. Quick Check:

   Indent loop body statements properly [OK]

Hint: Indent all loop statements to avoid errors [OK]

Common Mistakes:

• Ignoring indentation rules in pseudocode
• Assuming missing END FOR error
• Thinking variable initialization is wrong

5. You want to write pseudocode to find the largest number in a list of 4 numbers: 3, 7, 2, 5. Which pseudocode correctly plans this?

hard

A. SET max TO first number
FOR each number IN list
IF number > max THEN
SET max TO number
END IF
END FOR
PRINT max

B. SET max TO 0
FOR i FROM 1 TO 4
IF list[i] < max THEN
SET max TO list[i]
END IF
END FOR
PRINT max

C. FOR number IN list
PRINT number
END FOR
PRINT max

D. SET max TO 0
IF 3 < max THEN SET max TO 3
IF 7 < max THEN SET max TO 7
IF 2 < max THEN SET max TO 2
IF 5 < max THEN SET max TO 5
PRINT max

Solution

1. Step 1: Understand the goal to find the largest number

   We start with max as the first number, then compare each number to max, updating max if larger.

2. Step 2: Check each option for correct logic

   SET max TO first number FOR each number IN list IF number > max THEN SET max TO number END IF END FOR PRINT max correctly uses a loop and IF to update max. SET max TO 0 FOR i FROM 1 TO 4 IF list[i] < max THEN SET max TO list[i] END IF END FOR PRINT max uses wrong comparison. FOR number IN list PRINT number END FOR PRINT max only prints numbers. SET max TO 0 IF 3 < max THEN SET max TO 3 IF 7 < max THEN SET max TO 7 IF 2 < max THEN SET max TO 2 IF 5 < max THEN SET max TO 5 PRINT max uses wrong comparison.

3. Final Answer:

   SET max TO first number FOR each number IN list IF number > max THEN SET max TO number END IF END FOR PRINT max -> Option A

4. Quick Check:

   Loop + IF to update max = SET max TO first number FOR each number IN list IF number > max THEN SET max TO number END IF END FOR PRINT max [OK]

Hint: Use loop and IF to update max value [OK]

Common Mistakes:

• Using wrong comparison sign
• Not initializing max properly
• Writing repetitive IFs instead of loop