Error when picking out unique numbers in an array

This is a problem in my textbook for my Java class where the user enters 10 integers. The program is supposed to read all integers and only display the unique numbers (not duplicated) as the output. I am having trouble understanding why my output is not picking up the last unique value in the array (5). Can anyone give some insight to this issue? Any help would be appreciated. (Since we are in the early stages of the class and understanding the language, our assignment is to complete this using a nested loop.)

-The output is:
Enter 10 numbers: 1 2 3 2 1 6 3 4 5 2
The number of distinct numbers is 5
The distinct numbers are: 1 2 3 6 4

-When it should be:
Enter 10 numbers: 1 2 3 2 1 6 3 4 5 2
The number of distinct numbers is 6
The distinct numbers are: 1 2 3 6 4 5

public class ch7e5{

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        

        System.out.print("Enter 10 numbers: ");

        int[] numberArray = new int[10];
        //create array for all numbers

        int[] distinctArray = new int[10];
        //create array for distinct numbers

        int distinct = 0;

        for (int i = 0; i < 10; i++)
       
            
            numberArray[i] = input.nextInt();

        distinctArray[0] = numberArray[0];
        //first value will be distinct

        for (int i = 1; i < numberArray.length; i++) {
        //loop to go through remaining values in numberArray

            boolean exists = false;
            //create boolean
            
            for (int j = 0; j < numberArray.length; j++) {
            //loop to check if value exists already in distinctArray

                if (numberArray[i] == distinctArray[j]) {

                    exists = true;
                    

                    break;
                    //break out of inner loop
                    
                }
            }

            if (exists == false) {
            //if value is unique then add it to the distinct array

                
                distinct++;
                distinctArray[distinct] = distinctArray[i];

                

            }
        }
        //}

        System.out.println("The number of distinct numbers is " + distinct);

        System.out.print("The distinct numbers are: ");

        for (int k = 0; k < distinct; k++)
            
            System.out.print(distinctArray[k] + " ");

    }

}```




</details>


# 答案1
**得分**: 1

这里有3个不同的数字，1、2和3都不是其中的数字，因为它们各自出现了两次。输出应该是 6 4 5。我不确定你是怎么得到5个不同的数字的，也许输入有误？我建议首先不要使用扫描器，尝试手动将数字放入数组中。另外，我建议创建一个长度为10的布尔数组，初始值都设置为true，用于记录数字是否不同。如果一个数字出现两次，数组中对应的布尔值将被设置为false。一旦我编写完代码，我会在下面更新。

编辑：显然，有重复的数字并不会从不同的数字列表中删除。如果是这种情况，请详细说明一下标题。

以下是你的代码：

```java
public class Main {
  public static void main(String[] args) {
    int inputs = 3;
    int[] numberArray = new int[inputs];
    int distinct = 0;
    boolean[] mirror = new boolean[inputs];

    //只是设置数组
    for(int i = 0; i < numberArray.length; i++) {
      //numberArray[i] = i;
      mirror[i] = true;
    }
    numberArray[0] = 1;

    //找出哪些数字不是不同的
    for (int x = 0; x < numberArray.length; x++) {
      for (int y = 0; y < numberArray.length; y++) {
        System.out.println("x is " + x);
        System.out.println("y is " + y);
        if(numberArray[x] == numberArray[y] && x != y) {
          System.out.println(numberArray[x] + " is not distinct");
          mirror[x] = false; //如果数组中的当前位置与其他位置相匹配，数字就不是不同的
        }
      }
    }

    //计算有多少是不同的
    for(int j = 0; j < inputs; j++) {
      if(mirror[j]) {distinct++;}
    }

    //输出文本
    System.out.println("The number of distinct numbers is " + distinct);
    System.out.print("The distinct numbers are: ");
    for(int k = 0; k < inputs; k++){
      if(mirror[k]) {System.out.print(numberArray[k] + " ");}
    }
  }
}

public class Main {
  public static void main(String[] args) {
    int inputs = 3;
    int[] numberArray = new int[inputs];
    int distinct = 0;
    boolean[] mirror = new boolean[inputs];

    //just setting up arrays
    for(int i = 0; i < numberArray.length; i++) {
      //numberArray[i] = i;
      mirror[i] = true;
    }
    numberArray[0] = 1;

    //finds out what numbers are not distinct
    for (int x = 0; x < numberArray.length; x++) {
      for (int y = 0; y < numberArray.length; y++) {
        System.out.println("x is " + x);
        System.out.println("y is " + y);
        if(numberArray[x] == numberArray[y] && x != y) {
          System.out.println(numberArray[x] + " is not distinct");
          mirror[x] = false;//if current position in array matches any other position, number is not distinct
        }
      }
    }

    //calculates how many are distinct
    for(int j = 0; j < inputs; j++) {
      if(mirror[j]) {distinct++;}
    }

    //outputs text
    System.out.println("The number of distinct numbers is " + distinct);
    System.out.print("The distinct numbers are: ");
    for(int k = 0; k < inputs; k++){
      if(mirror[k]) {System.out.print(numberArray[k] + " ");}
    }
  }
}

答案2

得分: 0

错误出现在这里

distinct++;
distinctArray[distinct] = distinctArray[i];

1、在将数字添加到distinctArray后，您应该递增distinct；2、您应该执行distinctArray[distinct] = numberArray[i]。目前，您只是将可能是0的内容放入distinctArray[distinct]。

更简洁的方法是这样的

int[] distinctArray = Arrays.stream(numberArray).distinct().toArray();
System.out.println("不同数字的数量为：" + distinctArray.length);
System.out.print("不同的数字为：");
for (int d : distinctArray) System.out.print(d + " ");

输出：

输入10个数字：1 2 3 2 1 6 3 4 5 2
不同数字的数量为：6
不同的数字为：1 2 3 6 4 5

distinct++;
distinctArray[distinct] = distinctArray[i];

int[] distinctArray = Arrays.stream(numberArray).distinct().toArray();
System.out.println("The number of distinct numbers is " + distinctArray.length);
System.out.print("The distinct numbers are: ");
for (int d : distinctArray) System.out.print(d + " ");

Enter 10 numbers: 1 2 3 2 1 6 3 4 5 2
The number of distinct numbers is 6
The distinct numbers are: 1 2 3 6 4 5