Question textDefine a function named withoutLastDigit that when passed an integer, returns its last digit. Please see the test cases for examples. Some trivial test cases are hidden to combat hard-coding.For example:[table]
Test | Result int a = 1729; println(withoutLastDigit(a)); | 172 int x = -35; println(withoutLastDigit(x)); | -3
[/table] Answer:(penalty regime: 0 %)Ace editor not ready. Perhaps reload page?Falling back to raw text area.Check Question 3

Question

BlackTom AI · Accepted Answer

Integer division by 10 removes the last decimal digit of an integer, so the function can simply return n / 10.

1) Relevant knowledge points and concepts
- In Java, dividing two integers performs integer division: the fractional part is discarded (truncated toward zero).  
- Example: 1729 / 10 = 172 (1729 ÷ 10 = 172.9, fractional .9 discarded). For negatives, -35 / 10 = -3 (−35 ÷ 10 = −3.5, truncated toward zero gives −3).  
- Alternative approaches (string slicing, Math.floorDiv, or modulo) are unnecessary here; note Math.floorDiv uses floor semantics and would produce −4 for −35, which is not desired.

2) Step-by-step reasoning
- The goal is to return the integer formed by removing the last digit of n. That is exactly the integer quotient of n divided by 10.  
- Implement a method that accepts an int and returns n / 10.

3) Calculations / intermediate steps
- For n = 1729: 1729 / 10 = 172.9 → integer division → 172 (remainder 9).  
- For n = −35: −35 / 10 = −3.5 → integer division truncates toward zero → −3 (remainder −5 in Java’s % semantics, but remainder is not needed here).

4) Why the correct answer is correct
- Returning n / 10 yields the integer quotient after dividing by 10, which corresponds exactly to dropping the last digit for both positive and negative integers under Java’s integer division rules. The provided examples match this behavior.

5) Other approaches and why they are not used
- Using modulo (n % 10) returns the last digit, not the number without the last digit.  
- Using Math.floorDiv(n, 10) would floor toward −∞ and give −4 for −35, which contradicts the example.  
- Converting to String and trimming is unnecessary and less efficient.

6) Conclusion
The correct implementation is:
public static int withoutLastDigit(int n) {
    return n / 10;
}
This matches the provided answer.

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