Chapter 3 - Tutorial 5

Pseudocode Indentation Rules Recall

IF Statement Indentation Rules

Rule 1: ALL statements inside an IF block MUST be indented

CORRECT - Statements inside IF are indented:

BEGIN
    READ age
    IF age >= 18 THEN
        PRINT "You are eligible to vote"
        PRINT "Please bring your ID"
        PRINT "Voting booth is open"
    ENDIF
    PRINT "Thank you"
END

WRONG - No indentation inside IF:

BEGIN
    READ age
    IF age >= 18 THEN
    PRINT "You are eligible to vote"
    PRINT "Please bring your ID"
    PRINT "Voting booth is open"
    ENDIF
    PRINT "Thank you"
END

Rule 2: IF-ELSE statements require proper indentation for BOTH parts

CORRECT - Both IF and ELSE parts indented:

BEGIN
    READ score
    IF score >= 80 THEN
        PRINT "Excellent! You passed with distinction"
        grade = "A"
    ELSE
        PRINT "You need to improve"
        grade = "F"
    ENDIF
    PRINT "Your grade is: " + grade
END

WRONG - Inconsistent indentation:

BEGIN
    READ score
    IF score >= 80 THEN
        PRINT "Excellent! You passed with distinction"
    grade = "A"
    ELSE
        PRINT "You need to improve"
        grade = "F"
    ENDIF
    PRINT "Your grade is: " + grade
END

WHILE Loop Indentation Rules

Rule 3: ALL statements inside a WHILE loop MUST be indented

CORRECT - Loop body properly indented:

BEGIN
    counter = 1
    WHILE counter <= 5 DO
        PRINT "Count: " + counter
        counter = counter + 1
        PRINT "Next iteration coming..."
    ENDWHILE
    PRINT "Loop finished"
END

WRONG - Loop body not indented:

BEGIN
    counter = 1
    WHILE counter <= 5 DO
    PRINT "Count: " + counter
    counter = counter + 1
    PRINT "Next iteration coming..."
    ENDWHILE
    PRINT "Loop finished"
END

Nested Structures - Double Indentation

Rule 4: Nested IF inside WHILE requires DOUBLE indentation

CORRECT - Nested IF properly indented:

BEGIN
    num = 1
    WHILE num <= 10 DO
        IF num % 2 = 0 THEN
            PRINT num + " is even"
        ELSE
            PRINT num + " is odd"
        ENDIF
        num = num + 1
    ENDWHILE
END

Level 0: BEGIN/END (no indentation)
Level 1: WHILE body (4 spaces)
Level 2: IF/ELSE body (8 spaces)

Visual Indentation Guide

BEGIN                          ← Level 0 (No indentation)
    READ value                 ← Level 1 (Inside BEGIN block)
    WHILE value > 0 DO         ← Level 1 (Same level as READ)
        PRINT "Processing..."  ← Level 2 (Inside WHILE)
        IF value > 100 THEN    ← Level 2 (Same level as PRINT)
            PRINT "Large"      ← Level 3 (Inside IF)
        ELSE                   ← Level 2 (Same level as IF)
            PRINT "Small"      ← Level 3 (Inside ELSE)
        ENDIF                  ← Level 2 (Closes IF)
        value = value - 1      ← Level 2 (Inside WHILE)
    ENDWHILE                   ← Level 1 (Closes WHILE)
    PRINT "Done"               ← Level 1 (After WHILE)
END                            ← Level 0 (Closes BEGIN)

Exercise 1 Task

Convert the below pseudocode into a flowchart and IPO table.

Start
       read usage
       if usage <= 1000
            charge = usage x 0.20
       else 
            charge = (1000 x 0.20 ) +   
            ((usage - 1000) x 0.10)
       end if 
      print charge
Stop

Exercise 2 Task

Convert the below IPO table into a flowchart and pseudocode.

INPUT	PROCESS	OUTPUT
number for 5 times	repeat determine largest based on number for 5 times	largest

Exercise 3 Task

Convert the below flowchart into an IPO table and pseudocode.

Exercise 4 Task

Convert the following pseudocode into a flowchart and IPO

Start
    read temperature
    count = 0
    while temperature != -999
        if temperature > 30
            print "Hot day"
            count = count + 1
        else
            if temperature < 10
                print "Cold day"
            else
                print "Pleasant day"
            end if
        end if
        read temperature
    end while
    print "Number of hot days: " + count
Stop

Exercise 5 Task

Given the following pseudocode, create an IPO table and flowchart.

BEGIN
      total = 0
      read score
      while score != 0
          if score >= 80
              print "Pass"
          else
              print "Fail"
          endif
          total = total + score
          read score
      endwhile
      print "Total: " + total
END