ICS3U and ICS4U exam review: two mock exams and how to mark them

Source: The Ontario Curriculum, Grades 10 to 12: Computer Studies (2008), sections on the achievement chart and on evaluation and reporting, read 22 October 2026. The percentage bands are paraphrased from the chart’s column headings. No ministry or school board has any part in these mocks.

Section 1: Knowledge and Understanding (12 marks)

1. (3 marks) Name the kind of error in each: (a) print("hello" with the closing bracket missing; (b) a program meant to average four numbers divides their total by 3; (c) a program reads nums[5] from a list of five numbers.
2. (2 marks) What does the loop below print?
3. (3 marks) What exact line does the Java statement below print?
4. (2 marks) Convert the binary number 101101 to decimal, then convert your answer to hexadecimal.
5. (2 marks) In one sentence each, define a parameter and a return value.

for k in range(10, 0, -3):
    print(k, end=" ")

System.out.println(17 / 5 + " " + 17 % 5 + " " + 17.0 / 5);

Section 2: Thinking (12 marks)

Question 6 (4 marks). Trace the program below and write exactly what it prints.

rows = 4
for r in range(1, rows + 1):
    line = ""
    for c in range(r):
        line = line + str(c + 1)
    print(line)

Question 7 (4 marks). This Java code should print the average of the three marks, about 81.67, but prints 81.0. Explain why, name the kind of error, and fix it.

int[] marks = {70, 85, 90};
int total = 0;
for (int m : marks) total += m;
double average = total / marks.length;
System.out.println(average);

Question 8 (4 marks). Choose four years to test the function below. For each, give the expected result and say what the test checks. Do not run it.

def is_leap_year(year):
    if year % 400 == 0:
        return True
    if year % 100 == 0:
        return False
    return year % 4 == 0

Section 3: Application (18 marks)

Question 9 (5 marks). Write a function count_vowels(word) that returns how many of a, e, i, o, u appear in a word, in upper or lower case.

Question 10 (8 marks). Store these five temperatures in an array or list: -3, 4, 11, -8, 6. Print their average, then print how many are above the average. Do not use a built-in average function.

Question 11 (5 marks). Write linear_search(values, target) that returns the index of the first value equal to target, or -1 if there is none.

Section 4: Communication (8 marks)

Question 12 (4 marks). In three or four sentences, explain the difference between a compiler and an interpreter, and say which one your class language uses.

Question 13 (4 marks). Write the pseudocode you would plan before coding Question 10. Use numbered steps and clear names.

def power(base, exp):
    if exp == 0:
        return 1
    half = power(base, exp // 2)
    if exp % 2 == 0:
        return half * half
    return half * half * base

1. Question 1 (4 marks, Thinking). What does power(2, 10) return, and how many times is power called in total, counting the first call? Why is that fewer than ten?
2. Question 2 (4 marks, Knowledge and Understanding). Selection sort is run on a list of six numbers. How many comparisons does it make if the list is already sorted, and how many if it is shuffled? Give the formula for n items, and name a sort that does far fewer comparisons on an already sorted list.
3. Question 3 (4 marks, Thinking). Using the list below, write each middle index and value that binary search checks when searching for 58, and then for 10. Say what each search returns.
4. Question 4 (10 marks, Application). Write a class Clock that stores hours (0 to 23) and minutes (0 to 59) as private data, refuses an invalid time when it is created, has a method tick() that moves forward one minute and wraps from 23:59 to 00:00, and prints itself as HH:MM.
5. Question 5 (6 marks, Application). Write code that prints the total of each column of the grid below as a list.
6. Question 6 (6 marks, Communication). Explain unit testing, integration testing and regression testing, with one example of each using your Clock class.
7. Question 7 (6 marks, Thinking). What happens when power(2, -1) is called in Python? The same method written in Java with int division returns a number instead. What number, and why do the two languages differ? How would you fix the method?

vals = [3, 8, 12, 15, 21, 26, 30, 34, 41, 47, 52, 58, 63, 70, 77]
# binary search with lo = 0, hi = 14, mid = (lo + hi) // 2

grid = [[2, 7, 1, 8],
        [2, 8, 1, 8],
        [4, 5, 9, 0]]

print(15 // 4, 15 % 4, 15 / 4)

a = 5
b = 9
a = b
b = a
print(a, b)

print("ha" * 3)
print(3 > 2 and 2 > 3, 3 > 2 or 2 > 3)

c = 25
f = c * 9 / 5 + 32
print(f)

1. 3 3 3.75. // keeps the whole part, % gives the remainder, and / gives the exact decimal. 15 is 3 fours with 3 left over.
2. 9 9. After a = b, the 5 is gone. Then b = a copies 9 back into b. Swapping needs a third variable, or Python’s a, b = b, a.
3. hahaha. Multiplying text by a whole number repeats it.
4. False True. and needs both sides true; or needs at least one.
5. 77.0. 25 times 9 is 225, divided by 5 is 45.0, plus 32 is 77.0. The / makes it a decimal even though the answer is whole.