w3resource

Java String Exercises: Get the character (Unicode code point) before the specified index within the String

Java String: Exercise-3 with Solution

Write a Java program to get the character (Unicode code point) before the specified index within the String.

Sample Solution:

Java Code:

public class Exercise3 {

   public static void main(String[] args) {
  
    String str = "w3resource.com";
    System.out.println("Original String : " + str);
        
    // codepoint before index 1
    int val1 = str.codePointBefore(1);
    
   // codepoint before index 9
    int val2 = str.codePointBefore(9);
        
    // prints character before index1 in string
    System.out.println("Character(unicode point) = " + val1);
    // prints character before index9 in string
    System.out.println("Character(unicode point) = " + val2);
  }
}

Sample Output:

Original String : w3resource.com                                                                              
Character(unicode point) = 119                                                                                
Character(unicode point) = 99

Flowchart:

Flowchart: Java String  Exercises - Get the character (Unicode code point) before the specified index within the String

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Java Code Editor:

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Next: Write a java program to count a number of Unicode code points in the specified text range of a String.

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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