public class Test3 {

public static void change(int[] arr, int value) {

arr[0] = 100;

value = 200;

}

public static void main(String[] args) {

int[] nums = {10, 20};int num = 50;

change(nums, num);

System.out.println("nums[0]=" + nums[0] + ", num=" + num);

}

}

public class ArrayReverse {

public static void main(String[] args) {

int[] arr = {1, 2, 3, 4, 5};

// 补充循环代码，实现数组元素反转

for (int i = 0; i < ___________; i++) { 

int temp = arr[i];

arr[i] = arr[___________]; 

arr[___________] = temp; 

}

// 打印反转后的数组

for (int i : arr) {

System.out.print(i + " ");

}

}

}

public class BubbleSort {

public static void main(String[] args) {

int[] arr = {5, 3, 8, 1, 2};// 补充冒泡排序代码

for (int i = 0; i < arr.length - 1; i++) {

for (int j = 0; j < ___________; j++) {

if (___________ > ___________) {

int temp = arr[j];

arr[j] = ___________;

arr[j+1] = temp;

}

}

}

// 打印排序后的数组

for (int i : arr) {

System.out.print(i + " ");

}

}

}

public class ArrayMax {

public static void main(String[] args) {

int[] arr = {12, 45, 3, 67, 23, 9, 54};

// 初始化最大值为第一个元素

int max = ___________;

// 遍历数组，找出最大值

for (_________ i = 1; i < __________.length; i++) {

if (__________[i] > max) {

__________ = arr[i];

}

}

System.out.println("数组最大值: " + max);

}

}

public static int search(int[] arr, int key) {

int low = 0;

int high = arr.length - 1;

while (low <= high) {

int mid = (low + high) / 2;

if (key < arr[mid]) {

high = ___________;

} else if (key > arr[mid]) {

low = ___________;

} else {

return ___________;

}

}

return ___________;

}

public static void main(String[] args) {

int[] arr = {1, 3, 5, 7, 9};

System.out.println(search(arr, 5)); // 应输出2

System.out.println(search(arr, 6)); // 应输出-1

}

}

public class Test1 {

public static void main(String[] args) {

int x = 1;

int y = 2;

System.out.println(x++ + ++y);

System.out.println("x=" + x + ", y=" + y);

System.out.println((x > y) ? "x大" : "y大");

}

}

public class StringOperation {

public static void main(String[] args) {

String str = "Hello, World!";

System.out.println("长度: " + str.length());

System.out.println("第3个字符: " + str.charAt(2));

System.out.println("子串: " + str.substring(7, 12));

System.out.println("大写: " + str.toUpperCase());System.out.println("替换: " + str.replace('o', 'x'));

}

}

public class Test2 {

public static void main(String[] args) {

String s1 = "hello";

String s2 = "hello";

String s3 = new String("hello");

System.out.println(s1 == s2);

System.out.println(s1 == s3);

System.out.println(s1.equals(s2)); 

System.out.println(s1.equals(s3)); 

}

}

1. public class arrayProcessing {

2. public static void main(String args) {

3. int[] scores = new int[10];scores = {10, 20, 30};

4. // 填充数组

5. for (int i = 1; i <= scores.length; i++) {

6. scores[i] = i * 10;

7. }

8. // 计算总分

9. byte total = 0;

10. for (int i = 0; i < scores.length; i++) {

11. total += scores[i];

12. }

13. // 查找最高分

14. int maxScore = 0;

15. for (int i = 0; i < scores.length; i++) {

16. if (scores[i] > maxScore) {

17. maxScore = i;

18. }

19. }

20. // 计算平均值

21. int average = total / scores.length;

22. // 显示结果

23. System.out.println("总分: " + total);

24. System.out.println("平均分: " + average);

25. System.out.println("最高分: " + maxScore);

26. // 统计及格人数

27. int passCount;

28. for (int i = 0; i <= scores.length; i++) {

29. if (scores[i] >= 60) {

30. passCount++;break;

31. }

32. }

33. System.out.println("及格人数: " + passCount);

34. }

35. }

1. public class ErrorTest1 {

2. public static void main(String[] args) {

3. // 数组声明和初始化错误

4. int[] arr = new int[5];

5. arr = {1, 2, 3, 4, 5};

6.

7. // 循环和条件错误

8. for (int i = 0, i < arr.length, i++) {

9. if (arr[i] = 3) {

10. System.out.println("找到3");

11. }

12. }

13.

14. // 字符串比较错误

15. String s1 = "hello";

16. String s2 = new String("hello");

17. if (s1 == s2) {

18. System.out.println("字符串相等");

19. }

20.

21. // 集合使用错误

22. List<String> list = new ArrayList<>();

23. list.add("apple");

24. list.add("banana");

25. list.add(1, "orange");

26. list.remove("banana");

27. System.out.println(list.get(2));

28.

29. // 方法调用错误

30. int result = calculate(10, 0);

31. System.out.println("结果: " + result);

32. }

33.

34. public static int calculate(int a, int b) {

35. return a / b;

36. }

37.

38. // 重载方法错误

39. public void process(String str) {

40. System.out.println(str);

41. }

42.

43. public int process(String str) {

44. return str.length();

45. }

46.

47. // 变量作用域错误

48. for (int i = 0; i < 5; i++) {

49. int x = i * 2;

50. }

51. System.out.println(x);

52. }

1. public class ErrorTest2 {

2. public static void main(String[] args) {

3. // 实例化错误4. Animal animal = new Animal();

5. Dog dog = new Animal();

6.

7. // 静态使用错误

8. Counter c1 = new Counter();

9. Counter c2 = new Counter();

10. System.out.println(c1.count + " " + c2.count);

11.

12. // 接口实现错误

13. MyInterface obj = new MyInterface() {

14. // 缺少method2的实现

15. };

16.

17. // 访问权限错误

18. Student student = new Student();

19. student.name = "John";

20. System.out.println(student.getPassword());

21. }

22. }

23.

24. // 抽象类定义

25. abstract class Animal {

26. public abstract void sound();

27.

28. public void eat() {

29. System.out.println("动物吃东西");

30. }

31. }

32.

33. class Dog extends Animal {

34. public void sound() {

35. System.out.println("汪汪");

36. }

37.

38. public void bark() {

39. System.out.println("大声叫");

40. }

41. }

42.

43. // 静态变量使用

44. class Counter {

45. public static int count = 0; // 应为static

46.

47. public Counter() {

48. count++;49. }

50. }

51.

52. // 接口定义

53. interface MyInterface {

54. void method1();

55. void method2();

56. }

57.

58. // 封装性错误

59. class Student {

60. private String name;

61. private String password;

62.

63. public String getName() {

64. return name;

65. }

66.

67. private String getPassword() {

68. return password;

69. }

70. }

71.

72. // final使用错误

73. class Base {

74. public final void display() {

75. System.out.println("Base display");

76. }

77. }

78.

79. class Derived extends Base {

80. public void display() {

81. System.out.println("Derived display");

82. }

83. }

84.

85. // 构造方法错误

86. class TestClass {

87. private int value;

88.

89. public TestClass(int value) {

90. this.value = value;

91. }

92.

93. public void show() {94. System.out.println(value);

95. }

96.

97. // 缺少无参构造方法，但main中尝试使用 // 错误9

98. }

99.

100. // 数组协变错误

101. class Main {

102. public static void main(String[] args) {

103. Object[] objArray = new String[5];

104. objArray[0] = new Integer(10);

105. }

106. }

1. import java.io.*;

2. import java.util.*;

3.

4. public class ErrorTest3 {

5. public static void main(String[] args) {

6. // 文件读取错误

7. readFile("nonexistent.txt");

8.

9. // 空指针异常

10. String text = null;

11. System.out.println(text.length());

12.

13. // 数字格式异常14. String numStr = "abc";

15. int number = Integer.parseInt(numStr);

16.

17. // 资源管理错误

18. FileInputStream fis = new FileInputStream("test.txt");

19. int data = fis.read();

20. // 忘记关闭流

21.

22. // 集合并发修改

23. List<String> items = new ArrayList<>();

24. items.add("A");

25. items.add("B");

26. items.add("C");

27. for (String item : items) {

28. if (item.equals("B")) {

29. items.remove(item);

31. }

32.

33. // 类型转换异常

34. Object obj = "hello";

35. Integer num = (Integer) obj;

36.

37. // 数组存储异常

38. String[] strArray = new String[5];

39. Object[] objArray = strArray;

40. objArray[0] = Integer.valueOf(1);

41.

42. // 方法递归错误

43. infiniteRecursion();

44.

45. // 日期时间使用错误

46. Date date = new Date(2024, 1, 1);

47. System.out.println(date);

48.

49. // 数学计算错误

50. int result = 100 / 0;

51. System.out.println(result);

52. }

53.

54. public static void readFile(String filename) {

55. // 方法声明没有throws，但内部有受检异常 // 错误补充

56. File file = new File(filename);

57. FileInputStream fis = new FileInputStream(file);

58. fis.close();59. }

60.

61. public static void infiniteRecursion() {

62. infiniteRecursion();

63. }

64.

65. // 克隆方法错误

66. class Person implements Cloneable {

67. private String name;

68.

69. public Object clone() {

70. return this; // 错误：应该深拷贝

71. }

72. }

73. }