[英]How to create an array from the contents of a text file to be sorted?
該程序采用這三個數組,並使用插入排序對它們進行排序,並對排序后對每個數組執行的比較和交換次數進行計數。
我現在正在嘗試測試在文本文件上制作的其他三個數組。 這三個文本文件只是數字列表,第一個文本文件稱為“ array4.txt”,其數字列表按順序包含1到2000。
第二個文件稱為“ array5.txt”,其數字列表按降序包含2000到1。 最后,第三個文件稱為“ array6.txt”,其數字列表包含一個從1到2000的隨機混合數字的列表,包括1和2000,無重復。
我的目標是讀取這些文件並將它們的值放入一個實際的數組中,並且讓我的插入排序方法讀取它們,對其進行排序並計算比較和交換的次數,就像我對前三個數組所做的一樣。
我對Java還是很陌生,不知道該怎么做。
import java.util.Scanner;
import java.io.*;
public class InsertionSort
{
public static void main(String args[]) throws IOException
{
int[] Array = {1,2,3,4,5,6,7,8,9,10};
int[] Array2 = {10,9,8,7,6,5,4,3,2,1};
int[] Array3 = {1,10,2,9,3,8,4,7,5,6};
System.out.println("Insertion Sort: ");
System.out.println();
System.out.println("Best Case Scenario: ");
printArray(Array);
insertionSort(Array);
System.out.println("Worst Case Scenario: ");
printArray(Array2);
insertionSort(Array2);
System.out.println("Average Case Scenario: ");
printArray(Array3);
insertionSort(Array3);
}
public static void insertionSort(int[] list)
{
int comps = 0, swaps = 0;
for(int i = 1; i < list .length; i++) {
int j = i;
// compare i with sorted elements and insert it
// sorted elements: [0..i-1]
while (j > 0 && list[j] < list[j - 1]) {
int temp = list[j];
list[j] = list[j - 1];
list[j - 1] = temp;
swaps++;
comps++; // loop condition true
j--;
}
comps++; // checking loop condition when false
}
//printArray(list);
System.out.println("Comparisons: " + comps
+ " Swaps: " + swaps);
System.out.println();
}
static void printArray(int[] array){
for(int i=0; i < array.length; i++)
{
System.out.print(array[i] + " ");
}
System.out.println();
}
}
這就是我想出的。 希望能幫助到你!
package com.company;
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
public class Main {
public static void main(String[] args) throws FileNotFoundException {
// Replace array.txt with the name of your txt file and your path
Scanner fileScanner = new Scanner(new File("array.txt"));
// Counter variable so we'll know the size of the array we'll need
int counter = 0;
// Iterate through the file counting the number of integers and incrementing the counter variable
while(fileScanner.hasNextInt()){
counter++;
fileScanner.nextInt();
}
// Reset the scanner to the beginning of the txt file
fileScanner = new Scanner(new File("array.txt"));
// Scan each integer into the array
int [] array = new int[counter];
for (int i = 0; i < array.length; ++i) array[i] = fileScanner.nextInt();
}
}
干得好:
public void getIt() {
List<Integer> ints = new ArrayList(); //temporary holder
try (Scanner scanner = new Scanner("filename.txt")) { //open a scanner that will scan our file
scanner.forEachRemaining(line -> { //iterate through each line in our file
String[] numberStrings = line.split(","); // the comma is your presumed delimeter IF one exists
for (int x = 0; x < numberStrings.length; x++) { // loop through each item separated by a comma on each line
ints.add(Integer.parseInt(numberStrings[x])); // turn this string into an int and add it to your list
}
});
}
Integer[] integerArray = ints.toArray(new Integer[ints.size()]); //transform our list into an array
}
如果每行只有一個數字,則不需要for循環或forEachRemaining內部的line.split
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