Final Practice Exam A

25 questions · 8 sections · 90 minutes · closed book — no compiler, no notes. Write every answer on paper before opening the single key at the bottom. Section weights mirror the course’s emphasis: the trace and predict questions are the heart of the exam.

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Instructions

1. Time yourself — 90 minutes, one sitting. The pacing below is per section.
2. Answer every question; there is no penalty for a wrong attempt.
3. Scoring: each question = 1 raw mark (some questions award partial marks as marked). Total = 25, weighted to 100.
4. After scoring, complete the post-exam worksheet at the bottom.

Section A — Core concepts (Q1–Q4)

Q1. [Easy] Order the edit–compile–run cycle and state what each stage consumes and produces.

Q2. [Easy] Give one difference between a syntax error and a logic error, with one example of each.

Q3. [Medium] What are the values and types of a and b?

int a = 7 / 2;
double b = 7 / 2.0;

Q4. [Medium] Why does the course use const for values like tax rates? Give two distinct reasons.

Section B — Input/output & strings (Q5–Q8)

Q5. [Easy] Write the one missing line so this prints the name correctly:

int age;
cin >> age;
// missing line here
string name;
getline(cin, name);

Q6. [Medium] What exactly does this print?

cout << setw(6) << 42 << "|" << fixed << setprecision(1) << 2.45;

Q7. [Medium] What does this print?

string s = "integration";
cout << s.size() << " " << s[4] << " " << s.substr(2, 4);

Q8. [Hard] A user types Ali Hassan for a name prompt read with cin >> name;. State exactly what name holds, what happens to Hassan, and which statement should have been used.

Section C — Conditions (Q9–Q11)

Q9. [Medium] Rewrite correctly: “in stock if quantity is at least 1 and at most 500”.

bool inStock = (qty >= 1) || (qty <= 500);   // fix this line

Q10. [Medium] What does this print for t = 72?

if (t >= 90)      cout << "A";
else if (t >= 80) cout << "B";
else if (t >= 70) cout << "C";
else              cout << "F";

Q11. [Hard] What does this print for x = 5? Explain the truth of each condition in one clause.

if (x > 3 && x < 10)   cout << "P";
if (x > 3 || x < 10)   cout << "Q";
if (x < 3 && x < 10)   cout << "R";

Section D — Loops & tracing (Q12–Q15)

Q12. [Medium] What does this print?

int sum = 0;
for (int i = 2; i <= 8; i += 2)
    sum += i;
cout << sum;

Q13. [Medium] What does this print?

int n = 406;
while (n > 0) {
    cout << n % 10;
    n /= 10;
}

Q14. [Hard] Complete the trace table (0.5 marks per correct row) for:

int a = 1, b = 1;
while (b < 20) {
    int next = a + b;
    a = b;
    b = next;
}
cout << a;

Then state the printed value.

Q15. [Hard] What does this print? Draw the nested-loop trace if unsure.

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= i; j++)
        cout << i * j << " ";
    cout << "| ";
}

Section E — Functions (Q16–Q18)

Q16. [Medium] What does this print?

int twist(int n) { return n * 3 - 1; }
int main() {
    cout << twist(twist(2));
}

Q17. [Medium] What does this print?

void scale(int& v, int f) { v *= f; }
int main() {
    int x = 6;
    scale(x, 10);
    cout << x;
}

Q18. [Hard] Write a complete function bool isPerfect(int n) — true when n equals the sum of its proper divisors (e.g. 28 = 1+2+4+7+14). Full marks for correct handling of n < 2. (3 marks: guard 0.5, loop 1.5, comparison 0.5, n<2 verdict 0.5.)

Section F — Collections & algorithms (Q19–Q21)

Q19. [Medium] What does this print?

vector<int> v = {5, 12, 9, 20, 3};
int best = v[0];
for (size_t i = 1; i < v.size(); i++)
    if (v[i] > best) best = v[i];
cout << best;

Q20. [Medium] After one pass of bubble sort (ascending, left to right) on {4, 7, 2, 9, 1}, what is the array?

Q21. [Hard] The array {3, 8, 12, 17, 25, 31} is searched for 17 by binary search. List the elements compared, in order. (1 mark per correct comparison, −1 for a wrong one, floor 0; 0.5 for naming the found index.)

Section G — Files & memory (Q22–Q23)

Q22. [Medium] marks.txt holds Ali 70\nSara 95\n. What does this print?

ifstream in("marks.txt");
string name; int m, total = 0, count = 0;
while (in >> name >> m) { total += m; count++; }
cout << count << " " << total;

Q23. [Hard] Circle each bug (1 mark each) and write the corrected line (0.5 each):

int main() {
    int* data = new int[5];
    if (data[0] == 0) return 0;      // (a)
    for (int i = 0; i <= 5; i++)     // (b)
        data[i] = i;
    delete data;                     // (c)
}

Section H — OOP & integration (Q24–Q25)

Q24. [Medium] What does this print?

class Wallet {
    int cents = 0;
public:
    void add(int c) { if (c > 0) cents += c; }
    int get() const { return cents; }
};
int main() {
    Wallet w;
    w.add(250); w.add(-30); w.add(50);
    cout << w.get();
}

Q25. [Hard] In one sentence each: (a) what virtual changes about a method call through a base-class reference; (b) why the destructor is called automatically and what that enables.

bool isPerfect(int n) {
    if (n < 2) return false;            // guard: 0, 1, negatives
    long long sum = 1;                  // 1 divides every n > 1
    for (int d = 2; d * d <= n; d++) {
        if (n % d == 0) {
            sum += d;
            if (d != n / d) sum += n / d;
        }
    }
    return sum == n;
}

Scoring guide

Section health check — a section below 50% points at a whole topic, not a bad day:

Post-exam worksheet (write it out — it is the real exam)

1. List every missed question and the one sentence why (what you confused it with).
2. Mark each miss: careless (you knew it), gap (you didn’t), misread (the answer was right for a different question).
3. For each gap, write the unit/module you will re-study and the date.
4. Retake when the worksheet’s dates have passed — not before.

Next: Final Exam B → · Hub