What will be the output of the following code snippet if the input number is 5?

int num = 5;
do {
System.out.println(num);
num++;
} while (num

Question

What will be the output of the following code snippet if the input number is 5?

int num = 5;
do {
    System.out.println(num);
    num++;
    } while (num < 10);

BlackTom AI · Accepted Answer

A do-while loop executes its body first and then evaluates the loop condition, so the loop body runs at least once regardless of the initial condition.

1. Relevant knowledge points and concepts
- Java's do-while loop syntax: do { body } while (condition);
- The body executes first, then the boolean condition is evaluated.
- System.out.println(num) prints the value followed by a newline.
- The loop variable is incremented inside the body (num++), so the condition uses the updated value on the next evaluation.

2. Step-by-step execution reasoning
- Initial statement: int num = 5;
- Enter the do block immediately (no prior condition check).
- Iteration 1:
  - Print current num: prints "5"
  - Execute num++ → num becomes 6
  - Evaluate condition: (num < 10) → (6 < 10) is true → loop repeats
- Iteration 2:
  - Print current num: prints "6"
  - num++ → num becomes 7
  - Condition: (7 < 10) true → repeat
- Iteration 3:
  - Print "7", increment to 8, (8 < 10) true
- Iteration 4:
  - Print "8", increment to 9, (9 < 10) true
- Iteration 5:
  - Print "9", increment to 10, (10 < 10) false → loop stops

3. Intermediate steps shown
- Printed sequence per iteration: 5, 6, 7, 8, 9 (each on its own line).
- Values of num after increments before condition check: 6, 7, 8, 9, 10.
- Loop terminates when num becomes 10 because 10 < 10 is false.

4. Why the correct answer is correct
Because the body runs first and increments num each time, the loop prints every integer starting at 5 and continues while the updated num is less than 10. That results in printing 5 through 9 inclusive.

5. Why the other options are incorrect
- "It will cause a runtime error.": No runtime error occurs; all operations are valid.
- "It will not print anything as the initial condition is false.": The do-while executes the body once before checking the condition, so it will print.
- "It will print the number 5 only.": It prints 5 and then continues because the condition becomes true for subsequent iterations until num reaches 10.

6. Conclusion
The code prints the numbers 5, 6, 7, 8, and 9 (each on a new line). This matches the provided correct answer: It will print numbers from 5 to 9.

What will be the output of the following code snippet if the input number is 5? int num = 5; do { System.out.println(num); num++; } while (num < 10); 单项选择题

类似问题

Which loop is guaranteed to execute at least once?

A do-while loop always executes its body at least once.

Which loop would you use if you want to ensure that some code executes at least once before checking the condition?

The program segment int counter = 1;do { printf("%d ", counter);} while (++counter <= 10); will _______________.

The implementation and loading phase of the Database Life Cycle (DBLC) involves _____.

Which of the following parameters is used to determine the concentration of protein in a spectrophotometer?

What are the units of absorbance?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单