swap 2 random string that had entered by keyboard on JAVA-CodePudding

I dont understand how to swap 2 random strings in LinkedList I know how to swap integers but strings are too diferent

import java.util.*;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        LinkedList<String> ll = new LinkedList<>();
        Scanner sc = new Scanner(System.in); 
        System.out.println("enter total count of elements -> ");
        int num = Integer.parseInt(sc.next());

        while(num>0) {
            ll.add(sc.next());
            num--; 
        }
        sc.close();
        System.out.println(ll);
    }
}

CodePudding user response：

Just another way. Read comments in code:

LinkedList<String> ll = new LinkedList<>(Arrays.asList(
        "Billy", "Tracey", "Fred", "Jack", "Joe", "Carlie"));
System.out.println("Original LinkedList contents:");
System.out.println(ll); // Display original List
System.out.println();
   
// Get a random index number
int swapFrom = new Random().nextInt(ll.size());
   
// Ensure the next random index number is different.
int swapTo = swapFrom;
while (swapTo == swapFrom) {
    swapTo = new Random().nextInt(ll.size());
}
   
System.out.println("Swap content at index "   swapFrom 
          " of LinkedList with content at index "   swapTo   ":");
String tmp = ll.get(swapTo);         // Temporarily hold content at index swapTo.
ll.set(swapTo, ll.get(swapFrom));    // Place what is at index swapFrom and overwrite what is at index swapTo.
ll.set(swapFrom, tmp);               // Overwrite what is at index swapfrom with what is in tmp.
System.out.println(ll);              // Display List with swapped elements.
System.out.println();

CodePudding user response：

There's a chance that no swap will occur with this but this is a possibility:

public static <T> void swapTwo(List<T> list) {
    int len = list.size();
    int ixOne = (int)(Math.random() * len);
    int ixTwo = (int)(Math.random() * len);
    Collections.swap(list, ixOne, ixTwo);
}