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Java String Exercises: Create a new string from a given string swapping the last two characters of the given string

Java String: Exercise-57 with Solution

Write a Java program to create a new string from a given string swapping the last two characters of the given string. The length of the given string must be two or more.

Sample Solution:

Java Code:

import java.util.*;
public class Main
{
public String lastTwo(String str)
{
if (str.length() < 2) return str;
return str.substring(0, str.length()-2)+ str.charAt(str.length()-1) + str.charAt(str.length()-2);
}
    public static void main (String[] args)
    {
      Main m= new Main();
      String str1 =  "string";
      System.out.println("The given strings is: "+str1);
      System.out.println("The string after swap last two characters are: "+m.lastTwo(str1));
    }
}	

Sample Output:

The given strings is: string
The string after swap last two characters are: strign

Pictorial Presentation:

Java String Exercises: Create a new string from a given string swapping the last two characters of the given string.

Flowchart:

Flowchart: Java String Exercises - Create a new string from a given string swapping the last two characters of the given string.

Visualize Java code execution (Python Tutor):


Java Code Editor:

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Previous: Write a Java program to append two given strings such that, if the concatenation creates a double characters then omit one of the characters.
Next: Write a Java program to read a string and return true if it ends with a specified string of length 2.

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Java: Tips of the Day

Array vs ArrayLists:

The main difference between these two is that an Array is of fixed size so once you have created an Array you cannot change it but the ArrayList is not of fixed size. You can create instances of ArrayLists without specifying its size. So if you create such instances of an ArrayList without specifying its size Java will create an instance of an ArrayList of default size.

Once an ArrayList is full it re-sizes itself. In fact, an ArrayList is internally supported by an array. So when an ArrayList is resized it will slow down its performance a bit as the contents of the old Array must be copied to a new Array.

At the same time, it's compulsory to specify the size of an Array directly or indirectly while creating it. And also Arrays can store both primitives and objects while ArrayLists only can store objects.

Ref: https://bit.ly/3o8L2KH