选择排序在更大项目中的实现

Question

我需要做一个项目，最多生成 100 个随机数，然后显示它们，然后你 select 几种类型之一（select离子、气泡、插入、shell..)，并对它们进行排序。我已经完成了生成部分，但我遇到了第一次排序的问题 - selection 排序。它只显示零而不是我生成和排序的数字。

package projekt;

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

public class Projekt {

    public static void main(String[] args) {
        int[] tablica;
        Scanner odczyt = new Scanner(System.in);

        System.out.println("Give number of elements (max 100): ");
        int liczbaElementow = odczyt.nextInt();
        tablica = new int[liczbaElementow];

        if (liczbaElementow <= 100 && liczbaElementow > 0){
            System.out.println("Generated:");
            Random Generator = new Random();
            for (int idx = 1; idx <= liczbaElementow; ++idx){
                int randomInt = Generator.nextInt(101);
                System.out.print(" " +randomInt);
            }

            {
                System.out.println(" ");
                System.out.print("Choose sorting method (1, 2 lub 3):");
            }
            Scanner odczyt2 = new Scanner(System.in);
            int ktoresort = odczyt2.nextInt();

            switch (ktoresort) {
                case 1: System.out.println("SORT 1");
                {
                    {
                        int min = 0;

                        for(int i = 0;i<liczbaElementow;i++)
                        {
                            min = i;
                            for(int j = i + 1;j<liczbaElementow;j++)
                            {
                                if(tablica[j] < tablica[min]) { min = j;}
                            }
                            int temp = tablica[i];
                            tablica[i] = tablica[min];
                            tablica[min] = temp;
                            System.out.println(tablica[i]);
                        }
                    }
                }
                break;
                case 2: System.out.println("SORT 2");
                break;
                case 3: System.out.println("SORT 3");
                break;
                default:  System.out.println("incorrect value");  
                break;
            }   

            odczyt2.close();    
        }
        else if (liczbaElementow==0) {
            System.out.println("entered 0");        
        }

        else{
            System.out.println("value is biger than 100");  
        }
    }
}

Answer 1

在你的代码中，你从未将生成的值添加到 tablica 这里有解决方案我的朋友

public class Projekt {

public static void main(String[] args) {


    int[] tablica;
    Scanner odczyt = new Scanner(System.in);

    System.out.println("Give number of elements (max 100): ");
    int liczbaElementow = odczyt.nextInt();
    tablica = new int[liczbaElementow];


    if (liczbaElementow <= 100 && liczbaElementow > 0){

        System.out.println("Generated:");
        Random Generator = new Random();
        for (int idx = 1; idx <= liczbaElementow; ++idx){
            int randomInt = Generator.nextInt(101);
            System.out.print(" " +randomInt);
            tablica[idx-1]=randomInt;


        }

        {
            System.out.println(" ");
            System.out.print("Choose sorting method (1, 2 lub 3):");
        }
        Scanner odczyt2 = new Scanner(System.in);
        int ktoresort = odczyt2.nextInt();

        switch (ktoresort) {
            case 1: System.out.println("SORT 1");
                bubbleSort(tablica);
            break;
            case 2: System.out.println("SORT 2");
                insertionSort(tablica);
            case 3: System.out.println("SORT 3");
                shelSort(tablica);
                break;
            default:  System.out.println("incorrect value");
                break;
        }

        System.out.println(Arrays.toString(tablica));
        odczyt2.close();
    }
    else if (liczbaElementow==0) {
        System.out.println("entered 0");
    }

    else{
        System.out.println("value is biger than 100");
    }
}


public static void bubbleSort( int [ ] num )
{
    int j;
    boolean flag = true;   // set flag to true to begin first pass
    int temp;   //holding variable

    while ( flag )
    {
        flag= false;    //set flag to false awaiting a possible swap
        for( j=0;  j < num.length -1;  j++ )
        {
            if ( num[ j ] < num[j+1] )   // change to > for ascending sort
            {
                temp = num[ j ];                //swap elements
                num[ j ] = num[ j+1 ];
                num[ j+1 ] = temp;
                flag = true;              //shows a swap occurred
            }
        }
    }
}


public static void insertionSort( int [ ] num)
{
    int j;                     // the number of items sorted so far
    int key;                // the item to be inserted
    int i;

    for (j = 1; j < num.length; j++)    // Start with 1 (not 0)
    {
        key = num[ j ];
        for(i = j - 1; (i >= 0) && (num[ i ] < key); i--)   // Smaller values are moving up
        {
            num[ i+1 ] = num[ i ];
        }
        num[ i+1 ] = key;    // Put the key in its proper location
    }
}


public static void shelSort(int[] array) {
    int inner, outer;
    int temp;

    int h = 1;
    while (h <= array.length / 3) {
        h = h * 3 + 1;
    }
    while (h > 0) {
        for (outer = h; outer < array.length; outer++) {
            temp = array[outer];
            inner = outer;

            while (inner > h - 1 && array[inner - h] >= temp) {
                array[inner] = array[inner - h];
                inner -= h;
            }
            array[inner] = temp;
        }
        h = (h - 1) / 3;
    }
}

}

选择排序在更大项目中的实现

Selection sort implementation in a bigger project

java

sorting

selection