我不知道我是否正确编码，但有人可以确认我的doBubbleSort方法及其在main方法中的实现是否正确编程？我的编码要求我创建一个大小为20的数组，并用1到1000之间的随机整数填充它，而不用硬编码。结果应该显示原始的，未排序的整数列表;然后在单独的行上显示气泡排序算法的每个过程。我必须重复该程序，直到用户选择退出。 **我已经进行了编辑以确保无论我使用什么变量，它都是根据ArrayLists声明的。
我希望输出如何显示的示例如下所示（尽管在我尝试执行20时它只显示5个整数）：
未排序列表：68 3 298 290 1
通过1：3 68 290 1 298
传2：3 68 1 290 298
通过3：3 1 68 290 298
通过4：1 3 68 290 298
// Used to capture keyboard input
import java.util.*;
// Our class called BubbleSort
public class BubbleSort {
// Create doBubbleSort method
public static void doBubbleSort(ArrayList<Integer> arr) {
boolean needNextPass = true;
while (needNextPass) {
// Array may be sorted and next pass not needed
needNextPass = false;
// Swap list
for (int i = 0; i < arr.size()-1; i++) {
if (arr.get(i) > arr.get(i+1)) {
int temp = arr.get(i);
arr.set(i, arr.get(i+1));
arr.set(i+1, temp);
printOut(i+1, arr); // using printOut method
needNextPass = true; // Next pass still needed
}
}
}
}
private static void printOut(int pass, ArrayList<Integer> list) {
System.out.print("PASS " + pass + ": ");
for (int i = 0; i < list.size()-1; i++) {
System.out.print(list.get(i) + ", ");
}
// Shows very last integer with a period
System.out.print(list.get(list.size()-1) + ".");
System.out.println();
}
// Main method
public static void main(String[] args) {
ArrayList<Integer> array = new ArrayList<Integer>(); // Declare and instantiate a new ArrayList object
Scanner userChoice = new Scanner(System.in); // User input for quitting program
String choice = ""; // Will hold user choice to quit program
boolean inputFlag = false; // True if input is valid, false otherwise
// Repeat program until user chooses to quit
while (inputFlag = true) {
System.out.print("\nWould you like to continue the program? (Y/N): ");
choice = userChoice.nextLine();
if (choice.equalsIgnoreCase("Y")) {
try {
/* Create an array of size 20 and populate it with random integers between 1 and 1000.
Do not ask user for the numbers and do not hard code them */
for (int i = 0; i < 20; i++) {
int integer = (int)(1000.0 * Math.random());
array.add(integer);
}
System.out.print("\nUNSORTED LIST: ");
//Display the 20 size of the unsorted ArrayList
for (int i = 0; i < array.size() - 1; i++) {
System.out.print(array.get(i) + ", ");
}
// Shows very last integer with a period
System.out.print(array.get(array.size() - 1) + ".");
System.out.println();
doBubbleSort(array);
}
catch (IndexOutOfBoundsException e) {
System.out.println("\nThere is an out of bounds error in the ArrayList.");
}
}
else if (choice.equalsIgnoreCase("N")) {
break;
}
// Error message when inputting anything other than Y/N
else {
System.out.println("\nERROR. Only Y, y, N, or n may be inputted.");
System.out.println("Please try again.");
}
}
}
}
答案 0 :(得分：0)
你写了太多用于冒泡排序的锅炉板代码。对于冒泡排序，请使用递归方法。我为你写了简单的泡泡方法，用输出做你想做的事情
private int[] bubbleSort(int[] arr){
int c;
boolean isArranged = false;
for (int i = 0; i < arr.length; i++) {
if (i < (arr.length - 1) && arr[i] > arr[i+1]){
c = arr[i];
arr[i] = arr[i+1];
arr[i+1] = c;
isArranged = true;
}
}
if (isArranged){
return bubbleSort(arr);
}else{
return arr;
}
}
将其称为：
Scanner in = new Scanner(System.in);
int length = in.nextInt();
int[] arr = new int[length];
for (int i = 0; i < length; i++) {
arr[i] = in.nextInt();
}
Main main = new Main();
int[] newArr = main.bubbleSort(arr);
for (int i = 0; i < newArr.length; i++) {
System.out.print(newArr[i] + " ");
}
您可以编写ArrayList而不是int数组。
答案 1 :(得分：0)
继续你的实施，因为你似乎是刚刚学习这个，你应该改变一些事情。首先，既然你正在为doBubbleSort方法使用一个int数组，那么也可以在main方法中使用一个int数组。
bubblesort的实施也需要改变。你应该首先仔细研究它的逻辑。每次都要经历整个阵列。
// Create doBubbleSort method
public static void doBubbleSort(int[] arr) {
boolean needNextPass = true;
// Array may be sorted and next pass not needed
// Swap list
for (int i = 0; i < arr.length - 1; i++) {
if (needNextPass) {
needNextPass = false;
for (int j = arr.length - 1; j > i; j--) {
int temp;
if (arr[j] < arr[j - 1]) {
temp = arr[j - 1];
arr[j - 1] = arr[j];
arr[j] = temp;
needNextPass = true; // Next pass still needed
}
}
printOut(i + 1, arr); // using printOut method
}
}
}
然后，打印阵列。
private static void printOut(int pass, int[] list) {
System.out.print("PASS " + pass + ": ");
for (int i = 0; i < list.length - 1; i++) {
System.out.print(list[i] + ", ");
}
// Shows very last integer with a period
System.out.print(list[list.length - 1] + ".");
System.out.println();
}
现在的主要方法。我已经更改了输入处理部分以重新运行程序，并使用了最初发布的int数组。
// Main method
public static void main(String[] args) {
int[] array = new int[20]; // Declare and instantiate a new ArrayList object
Scanner userChoice = new Scanner(System.in); // User input for quitting program
boolean inputFlag = true; // True if input is valid, false otherwise
String choice;
// Repeat program until user chooses to quit
while (inputFlag == true) {
try {
/* Create an array of size 20 and populate it with random integers between 1 and 1000.
Do not ask user for the numbers and do not hard code them */
for (int i = 0; i < 20; i++) {
int integer = (int) (1000.0 * Math.random());
array[i] = integer;
}
System.out.print("\nUNSORTED LIST: ");
//Display the 20 size of the unsorted ArrayList
for (int i = 0; i < array.length - 1; i++) {
System.out.print(array[i] + ", ");
}
// Shows very last integer with a period
System.out.print(array[array.length - 1] + ".");
System.out.println();
doBubbleSort(array);
} catch (IndexOutOfBoundsException e) {
System.out.println("\nThere is an out of bounds error in the ArrayList.");
}
System.out.print("\nWould you like to continue the program? (Y/N): ");
choice = userChoice.nextLine();
while (!(choice.equalsIgnoreCase("Y")) && !(choice.equalsIgnoreCase("N"))) {
// Error message when inputting anything other than Y/N
System.out.println("\nERROR. Only Y, y, N, or n may be inputted.");
System.out.println("Please try again.");
choice = userChoice.nextLine();
}
if (choice.equalsIgnoreCase("N")) {
inputFlag = false;
}
}
}
}