如何打印线性搜索后找到元素的索引？JAVA

我正在制作一个程序，在这个程序中，使用线性搜索来迭代100个随机生成的小于10000的数字数组

用户输入开始编号、中间编号和结束编号，线性搜索将在数组中迭代，并告诉用户在哪个索引中找到了元素

我已经实现了线性搜索，一切似乎都很好，但在实现了线性搜索之后，我似乎无法打印出元素的索引

我提供了代码、输入和输出：

代码：

import java.util.Scanner;
import java.util.Random;
import java.util.Arrays;

public class App {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    // generating n, 0 < n < 10000 and 0 < length < 100
    Random rand = new Random();
    int[] arr = new int[100];
    for (int z = 0; z < arr.length; z++) {
      arr[z] = rand.nextInt(10000);

    }
    // sorting 
    Arrays.sort(arr);
    System.out.println(Arrays.toString(arr));

    int startNum = scanner.nextInt();
    int midNum = scanner.nextInt();
    int endNum = scanner.nextInt();

    // linear search
    for (int i = 0; i < arr.length; i++) {
        if (startNum == arr[i]) {
            System.out.println("Found");
        }
        else {
            System.out.println("Not Found");
            
        }
        // where I want to print out the final message such as "startNum found at i"
    }
}

boolean startNumFound = false, midNumFound = false, endNumFound = false;

for (int i = 0; i < arr.length; i++) {
    if (startNum == arr[i]) {
        System.out.println(startNum + " was found at index, " + i);
        startNumFound = true;
    } else if (midNum == arr[i]) {
        System.out.println(midNum + " was found at index, " + i);
        midNumFound = true;
    } else if (endNum == arr[i]) {
        System.out.println(endNum + " was found at index, " + i);
        endNumFound = true;
    }
}
if (!startNumFound) {
    System.out.println(startNum + " was not found");
}
if (!midNumFound) {
    System.out.println(midNum + " was not found");
}
if (!endNumFound) {
    System.out.println(endNum + " was not found");
}

import java.util.Scanner；
导入java.util.Random；
导入java.util.array；
公共类应用程序{
公共静态void main（字符串[]args）{
扫描仪=新的扫描仪（System.in）；
//生成n，0

}

输入： 254 1467 8185

输出：

import java.util.Scanner;
import java.util.Random;
import java.util.Arrays;

public class App {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    // generating n, 0 < n < 10000 and 0 < length < 100
    Random rand = new Random();
    int[] arr = new int[100];
    for (int z = 0; z < arr.length; z++) {
      arr[z] = rand.nextInt(10000);

    }
    // sorting 
    Arrays.sort(arr);
    System.out.println(Arrays.toString(arr));

    int startNum = scanner.nextInt();
    int midNum = scanner.nextInt();
    int endNum = scanner.nextInt();

    // linear search
    for (int i = 0; i < arr.length; i++) {
        if (startNum == arr[i]) {
            System.out.println("Found");
        }
        else {
            System.out.println("Not Found");
            
        }
        // where I want to print out the final message such as "startNum found at i"
    }
}

boolean startNumFound = false, midNumFound = false, endNumFound = false;

for (int i = 0; i < arr.length; i++) {
    if (startNum == arr[i]) {
        System.out.println(startNum + " was found at index, " + i);
        startNumFound = true;
    } else if (midNum == arr[i]) {
        System.out.println(midNum + " was found at index, " + i);
        midNumFound = true;
    } else if (endNum == arr[i]) {
        System.out.println(endNum + " was found at index, " + i);
        endNumFound = true;
    }
}
if (!startNumFound) {
    System.out.println(startNum + " was not found");
}
if (!midNumFound) {
    System.out.println(midNum + " was not found");
}
if (!endNumFound) {
    System.out.println(endNum + " was not found");
}

发现 找不到 找不到 找不到 找不到 找不到 找不到 不 …（是否继续打印未找到？）

---

我只想保持这个简单，谢谢

如果您想在循环外打印结果，那么只需定义另一个值为

-1

的变量，因为索引从零开始，然后将已建立元素的索引存储在其中，如果没有找到，则值将为

-1

，这意味着找不到：

// linear search
int index = -1;
for (int i = 0; i < arr.length; i++) {
    if (startNum == arr[i]) {
        index = i;
        break;
    }
}

if (index != -1) {
    System.out.print(startNum + " Found at index: " + index);
} else {
    System.out.println("Not Found");
}

//线性搜索
int指数=-1；
对于（int i=0；i

您可以为这三个数字中的每一个创建

boolean

变量，以跟踪它们是否被找到。无论在何处找到它们，都要打印它们的索引，并将相应的

布尔值

变量的值更改为

真值

循环终止后，检查这些

布尔

变量的值，如果其值未更改为

真

，则打印未找到消息

代码：

import java.util.Scanner;
import java.util.Random;
import java.util.Arrays;

public class App {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    // generating n, 0 < n < 10000 and 0 < length < 100
    Random rand = new Random();
    int[] arr = new int[100];
    for (int z = 0; z < arr.length; z++) {
      arr[z] = rand.nextInt(10000);

    }
    // sorting 
    Arrays.sort(arr);
    System.out.println(Arrays.toString(arr));

    int startNum = scanner.nextInt();
    int midNum = scanner.nextInt();
    int endNum = scanner.nextInt();

    // linear search
    for (int i = 0; i < arr.length; i++) {
        if (startNum == arr[i]) {
            System.out.println("Found");
        }
        else {
            System.out.println("Not Found");
            
        }
        // where I want to print out the final message such as "startNum found at i"
    }
}

boolean startNumFound = false, midNumFound = false, endNumFound = false;

for (int i = 0; i < arr.length; i++) {
    if (startNum == arr[i]) {
        System.out.println(startNum + " was found at index, " + i);
        startNumFound = true;
    } else if (midNum == arr[i]) {
        System.out.println(midNum + " was found at index, " + i);
        midNumFound = true;
    } else if (endNum == arr[i]) {
        System.out.println(endNum + " was found at index, " + i);
        endNumFound = true;
    }
}
if (!startNumFound) {
    System.out.println(startNum + " was not found");
}
if (!midNumFound) {
    System.out.println(midNum + " was not found");
}
if (!endNumFound) {
    System.out.println(endNum + " was not found");
}

boolean startNumFound=false，midNumFound=false，endNumFound=false；
对于（int i=0；i