Given: public class Test { private int sum; public int compute() { int x = 0; while(x < 3) { sum += x++; } return sum; } public static void main(String[] args) { Test t = new Test(); int sum =…

The correct answer is D. 6. D (6) is correct because sum is an instance variable that persists between calls - after the first t.compute(), this.sum equals 3 (0+1+2). The second call starts with this.sum already at 3, then adds 0+1+2 again, returning 6, which is what gets printed. C (3) is wrong because…

Controlling Program Flow

Question

Given:
public class Test {
private int sum;
public int compute() {
int x = 0;
while(x < 3) {
sum += x++;
}
return sum;
}
public static void main(String[] args) {
Test t = new Test();
int sum = t.compute();
sum = t.compute();
System.out.println(sum);
}
}
What is the result?

Options

A9
BAn exception is thrown at runtime.
C3
D6

How the community answered

(22 responses)

A
5% (1)
B
5% (1)
C
14% (3)
D
77% (17)

Explanation

D (6) is correct because sum is an instance variable that persists between calls - after the first t.compute(), this.sum equals 3 (0+1+2). The second call starts with this.sum already at 3, then adds 0+1+2 again, returning 6, which is what gets printed.

C (3) is wrong because it assumes only the first compute() call matters, missing that the instance variable sum is stateful and carries over into the second call.

A (9) is a trap designed to catch students who lose track of what accumulates - there's no scenario in this code that produces 9; it's there to snag those who double-count or misread the loop boundary.

B is wrong because the code is syntactically and semantically valid - no null dereferences, no out-of-bounds access, no division by zero.

Memory tip: When you see a local variable in main with the same name as an instance field (int sum vs private int sum), that's a red flag - the local variable doesn't reset the instance field, so instance state silently accumulates across method calls.

Topics

#Post-increment operator#Instance variables#Loop state#Variable scope

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