Java编译时出现解决数组问题的错误。

huangapple
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英文:

java compile time error while solving array problem

问题

I am new to Java can't understand what i did wrong here

  1. import java.util.*;
  2. import java.io.*;
  4. public class Main {
  6.     public static void main(String[] args) throws Exception {
  7.         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  8.         int tc = Integer.parseInt(br.readLine().trim());
  9.         while (tc-- > 0) {
  10.             String[] inputLine;
  11.             int n = Integer.parseInt(br.readLine().trim());
  12.             int[] arr = new int[n];
  13.             inputLine = br.readLine().trim().split(" ");
  14.             for (int i = 0; i < n; i++) {
  15.                 arr[i] = Integer.parseInt(inputLine[i]);
  16.             }
  18.             int ans = new Solution().print2largest(arr, n);
  19.             System.out.println(ans);
  20.         }
  21.     }
  22. }
  24. // } Driver Code Ends
  27. //User function Template for Java
  29. class Solution {
  30.     int print2largest(int arr[], int n) {
  31.         int large = getLargest(arr, n);
  32.         int res = -1;
  33.         for (int i = 0; i < n; i++) {
  34.             if (arr[i] != arr[large]) {
  35.                 if (res == -1) {
  36.                     res = arr[i];
  37.                 } else if (arr[i] > arr[res]) {
  38.                     res = arr[i];
  39.                 }
  40.             }
  41.         }
  42.         return res;
  43.     }
  45.     public static int getLargest(int arr[], int n) {
  46.         int l = 0;
  47.         for (int i = 0; i < n; i++) {
  48.             if (arr[i] > arr[l]) {
  49.                 l = i;
  50.             }
  51.         }
  52.         return l;
  53.     }
  54. }

I got the following errors

  1. prog.java:53: error: class, interface, or enum expected
  2. public static int getLargest(int arr[], int n) {
  3.               ^
  4. prog.java:55: error: class, interface, or enum expected
  5. for(int i=0; i<n; i++){
  6. ^
  7. prog.java:55: error: class, interface, or enum expected
  8. for(int i=0; i<n; i++){
  9.                  ^
  10. prog.java:55: error: class, interface, or enum expected
  11. for(int i=0; i<n; i++){
  12.                       ^
  13. prog.java:58: error: class, interface, or enum expected
  14.         }
  15.         ^

This is my input -->
6
12 35 1 10 34 1

I am expecting this result for the given array -->
34

英文:

I am new to Java can't understand what i did wrong here

  1. import java.util.*;
  2. import java.io.*;
  3. public class Main {
  4. public static void main(String[] args) throws Exception {
  5. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  6. int tc = Integer.parseInt(br.readLine().trim());
  7. while (tc-- &gt; 0) {
  8. String[] inputLine;
  9. int n = Integer.parseInt(br.readLine().trim());
  10. int[] arr = new int[n];
  11. inputLine = br.readLine().trim().split(&quot; &quot;);
  12. for (int i = 0; i &lt; n; i++) {
  13. arr[i] = Integer.parseInt(inputLine[i]);
  14. }
  15. int ans = new Solution().print2largest(arr, n);
  16. System.out.println(ans);
  17. }
  18. }
  19. }
  20. // } Driver Code Ends
  21. //User function Template for Java
  22. class Solution {
  23. int print2largest(int arr[], int n) {
  24. int large = getLargest(arr,n);
  25. int res = -1;
  26. for(int i=0;i&lt;n;i++){
  27. if(arr[i]!= arr[large]){
  28. if(res == -1){
  29. res = arr[i];
  30. }
  31. else if(arr[i]&gt;arr[res]){
  32. res = arr[i];
  33. }
  34. }
  35. }
  36. return res;
  37. }
  38. }
  39. public static int getLargest(int arr[], int n) {
  40. int l = 0;
  41. for(int i=0; i&lt;n; i++){
  42. if(arr[i]&gt;arr[l]){
  43. l = i;
  44. }
  45. }
  46. return l;
  47. }

I got the following errors

  1. prog.java:53: error: class, interface, or enum expected
  2. public static int getLargest(int arr[], int n) {
  3. ^
  4. prog.java:55: error: class, interface, or enum expected
  5. for(int i=0; i&lt;n; i++){
  6. ^
  7. prog.java:55: error: class, interface, or enum expected
  8. for(int i=0; i&lt;n; i++){
  9. ^
  10. prog.java:55: error: class, interface, or enum expected
  11. for(int i=0; i&lt;n; i++){
  12. ^
  13. prog.java:58: error: class, interface, or enum expected
  14. }
  15. ^

`

This is my input -->
6
12 35 1 10 34 1

I am expecting this result for the given array -->
34

答案1

得分: 1

这个方法不属于任何类。
在Java中，方法应该属于一个类。
将它放在Solution类中，它将能够编译。

  1. public static int getLargest(int arr[], int n) {
  2.     int l = 0;
  3.     for(int i = 0; i < n; i++){
  4.         if(arr[i] > arr[l]){
  5.             l = i;
  6.         }
  7.     }
  8.     return l;
  9. }

你的代码还有另一个错误：

  1. if(arr[i] != arr[large]){
  2.     if(res == -1){
  3.         res = arr[i]; // 你正在保存元素而不是索引
  4.     }
  5.     else if(arr[i] > arr[res]){ // 但你正在与索引比较，可能会导致数组越界异常。应该像这样 arr[i] > res
  6.         res = arr[i]; // 你正在保存元素而不是索引
  7.     }
  8. }
英文:

this method is out of classes.
In Java methods should be part of class.
Keep it in class Solution, It will compile.

  1. public static int getLargest(int arr[], int n) {
  2. int l = 0;
  3. for(int i=0; i&lt;n; i++){
  4. if(arr[i]&gt;arr[l]){
  5. l = i;
  6. }
  7. }
  8. return l;
  9. }

There is another mistake with your code:

  1. if(arr[i]!= arr[large]){
  2. if(res == -1){
  3. res = arr[i]; // you are saving element not index
  4. }
  5. else if(arr[i]&gt;arr[res]){ // but you are comparing with index, it can give arrayOutOfBound exception. It should be like this arr[i]&gt;res
  6. res = arr[i]; // you are saving element not index
  7. }
  8. }

答案2

得分: 1

方法必须位于类结构内。

声明类（Java™教程 > 学习Java语言 > 类和对象）。

  1. import java.util.*;
  2. import java.io.*;
  4. public class Main {
  6.     public static void main(String[] args) throws Exception {
  7.         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  8.         int tc = Integer.parseInt(br.readLine().trim());
  9.         while (tc-- > 0) {
  10.             String[] inputLine;
  11.             int n = Integer.parseInt(br.readLine().trim());
  12.             int[] arr = new int[n];
  13.             inputLine = br.readLine().trim().split(" ");
  14.             for (int i = 0; i < n; i++) {
  15.                 arr[i] = Integer.parseInt(inputLine[i]);
  16.             }
  18.             int ans = new Solution().print2largest(arr, n);
  19.             System.out.println(ans);
  20.         }
  21.     }
  22. }
  24. // } Driver Code Ends
  27. //User function Template for Java
  29. class Solution {
  30.     int print2largest(int arr[], int n) {
  31.         int large = getLargest(arr, n);
  32.         int res = -1;
  33.         for (int i = 0; i < n; i++) {
  34.             if (arr[i] != arr[large]) {
  35.                 if (res == -1) {
  36.                     res = arr[i];
  37.                 } else if (arr[i] > arr[res]) {
  38.                     res = arr[i];
  39.                 }
  40.             }
  41.         }
  42.         return res;
  43.     }
  45.     public static int getLargest(int arr[], int n) {
  46.         int l = 0;
  47.         for (int i = 0; i < n; i++) {
  48.             if (arr[i] > arr[l]) {
  49.                 l = i;
  50.             }
  51.         }
  52.         return l;
  53.     }
  54. }
英文:

Methods must be within a class structure.

Declaring Classes (The Java&trade; Tutorials &gt; Learning the Java Language &gt; Classes and Objects).

  1. import java.util.*;
  2. import java.io.*;
  4. public class Main {
  6.     public static void main(String[] args) throws Exception {
  7.         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  8.         int tc = Integer.parseInt(br.readLine().trim());
  9.         while (tc-- &gt; 0) {
  10.             String[] inputLine;
  11.             int n = Integer.parseInt(br.readLine().trim());
  12.             int[] arr = new int[n];
  13.             inputLine = br.readLine().trim().split(&quot; &quot;);
  14.             for (int i = 0; i &lt; n; i++) {
  15.                 arr[i] = Integer.parseInt(inputLine[i]);
  16.             }
  18.             int ans = new Solution().print2largest(arr, n);
  19.             System.out.println(ans);
  20.         }
  21.     }
  22. }
  24. // } Driver Code Ends
  27. //User function Template for Java
  29. class Solution {
  30.     int print2largest(int arr[], int n) {
  31.         int large = getLargest(arr,n);
  32.         int res = -1;
  33.         for(int i=0;i&lt;n;i++){
  34.             if(arr[i]!= arr[large]){
  35.                 if(res == -1){
  36.                     res = arr[i];
  37.                 }
  38.                 else if(arr[i]&gt;arr[res]){
  39.                     res = arr[i];
  40.                 }
  41.             }
  42.         }
  43.         return res;
  44.     }
  46.     public static int getLargest(int arr[], int n) {
  47.         int l = 0;
  48.         for(int i=0; i&lt;n; i++){
  49.             if(arr[i]&gt;arr[l]){
  50.                 l = i;
  51.             }
  52.         }
  53.         return l;
  54.     }
  55. }

huangapple
  • 本文由 发表于 2023年6月18日 20:31:31
  • 转载请务必保留本文链接：https://go.coder-hub.com/76500554.html
  • algorithm
  • arrays
  • compiler-errors
  • data-structures
  • java
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