Find Bugs in the pseudocode

Question

// A high school is holding a recycling competition
// This program allows a user to enter a student's
// year in school (1 through 4)
// and number of cans collected
// Data is entered continuously until the user wnats to quit
// After headings, output is four lines
// one for each school year class
start
Declarations
num year
num cans
num SIZE = 4
num QUIT = 9
num collected[SIZE] = 0, 0, 0, 0
string HEAD1 = "Can Recycling Report"
string HEAD2 = "Year Cans Collected"
output "Enter year of student or ", QUIT, " to quit "
input year
while year <> QUIT
output "Enter number of cans collected "
input cans
collected[year] = collected[year] + cans
endwhile
output HEAD1
output HEAD2
while year <= SIZE
output year, collected[year - 1]
year = year + 1
endwhile
stop

DEBUG06-02.txt

// Program lets user input scores on four tests
// Average is computed and letter grade is determined
// Letter grades are based on 90 for an A, 80 for a B, and so on
start
string name
num score
num NUM_TESTS = 4
num NUM_RANGES = 5
num RANGES[NUM_RANGES] = 90, 80, 70, 60, 0
num QUIT = "ZZZZZ"
string GRADES[NUM_RANGES] = "A", "B", "C", "D", "F"
num total
num average
num sub
output "Enter student name or ", QUIT, " to quit "
input name
while name <> QUIT
sub = 0
while sub < NUM_TESTS
output "Enter score "
input score
total = total + score
endwhile
average = total / NUM_TESTS
sub = 0
while average < RANGES[NUM_TESTS]
sub = sub + 1
endwhile
letterGrade = GRADES[NUM_TESTS]
output name, letterGrade
output "Enter student name or ", QUIT, " to quit "
input name
endwhile
stop

DEBUG06-03.txt

// This program counts how many sales are made in each of 5 categories of products
start
Declarations
num category
num SIZE = 5
num QUIT = 9
num sales[SIZE] = 0, 0, 0, 0, 0
string HEAD1 = "Sales"
string HEAD2 = "Category Number of Sales"
output "Enter category ", QUIT, " to quit "
input category
while category = QUIT
if category >= 1 AND category < SIZE then
sales[category + 1] = sales[category - 1] + 1
else
output "Invalid category"
endif
output "Enter category ", QUIT, " to quit "
input category
endif
output HEAD1
output HEAD2
category = 0
while category <= SIZE
output category + 1, sales[category]
category = category + 1
endwhile
stop

Answer 1

To debug, always keep in your mind the value of variables at any time as the program proceeds, and think of exceptional values a user can enter.
Your program must expect users to enter anything because of human errors.
For example, for the recycling program:

// A high school is holding a recycling competition
// This program allows a user to enter a student's
// year in school (1 through 4)
// and number of cans collected
// Data is entered continuously until the user wnats to quit
// After headings, output is four lines
// one for each school year class
start
Declarations
num year
num cans
num SIZE = 4
num QUIT = 9
num collected[SIZE] = 0, 0, 0, 0
string HEAD1 = "Can Recycling Report"
string HEAD2 = "Year Cans Collected"
output "Enter year of student or ", QUIT, " to quit "
input year what if user enters 6? -5?
while year <> QUIT
output "Enter number of cans collected "
input cans
collected[year] = collected[year] + cans
endwhile
output HEAD1
output HEAD2
what is the value of "year" at this point, (logic requires it to be 0)
while year <= SIZE
output year, collected[year - 1]
year = year + 1
endwhile
stop

Answer 2

DEBUG06-02.txt

// Program lets user input scores on four tests
// Average is computed and letter grade is determined
// Letter grades are based on 90 for an A, 80 for a B, and so on
start
string name
num score
num NUM_TESTS = 4
num NUM_RANGES = 5
num RANGES[NUM_RANGES] = 90, 80, 70, 60, 0
num QUIT = "ZZZZZ"
string GRADES[NUM_RANGES] = "A", "B", "C", "D", "F"
num total
num average
num sub
output "Enter student name or ", QUIT, " to quit "
input name
while name <> QUIT
sub = 0
while sub < NUM_TESTS
output "Enter score "
input score
total = total + score
endwhile
average = total / NUM_TESTS
sub = 0
while average < RANGES[NUM_TESTS]
sub = sub + 1
endwhile
letterGrade = GRADES[NUM_TESTS]
output name, letterGrade
output "Enter student name or ", QUIT, " to quit "
input name
endwhile
stop

DEBUG06-03.txt

// This program counts how many sales are made in each of 5 categories of products
start
Declarations
num category
num SIZE = 5
num QUIT = 9
num sales[SIZE] = 0, 0, 0, 0, 0
string HEAD1 = "Sales"
string HEAD2 = "Category Number of Sales"
output "Enter category ", QUIT, " to quit "
input category
while category = QUIT
if category >= 1 AND category < SIZE then
sales[category + 1] = sales[category - 1] + 1
else
output "Invalid category"
endif
output "Enter category ", QUIT, " to quit "
input category
endif
output HEAD1
output HEAD2
category = 0
while category <= SIZE
output category + 1, sales[category]
category = category + 1
endwhile
stop