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Java codePointBefore Method

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The Java codePointBefore method is one of the Java String Method which is used to return the Unicode of the Character before the specified index position. In this article we will show you, How to use codePointBefore method in Java Programming language with example.

TIP: The index position of the codePointBefore Function will start from 0, Not 1.

Java codePointBefore method syntax

The basic syntax of the codePointBefore in Java Programming language is as shown below.

public int codePointBefore(int Index_Position) 

//In order to use in program
String_Object.codePointBefore(int Index_Position)
  • String_Object: Please specify the valid String Object.
  • Index_Position: Please specify the index position of a desired character.

TIP: Please refer ASCII Table to check the character codes of each and every character.

Return Value

The Java codePointBefore Function will return the Unicode value of a Character from String_Object at specified Index_Position minus 1. For example, if we specify codePointBefore(5), it will return the Unicode value of the character at index position 4. If we specify the Index position out of range or negative value, then codePointBefore Function will throw an error.

Java codePointBefore Example

The Java string codePointBefore method is used to return the Unicode value of a Character at specified index position minus 1. In this Java program, We are going to find the same.

JAVA CODE

package StringFunctions;

public class CodePointBefore {
	public static void main(String[] args) {
		String str = "Learn Free Java Tutorial";
		
		int a = str.codePointBefore(1);
		int b = str.codePointBefore(11);
		int c = str.codePointBefore(22);
		int d = str.codePointBefore(str.length()- 1);
		
		System.out.println( "Unicode Vlaue of Character at Index position 0 = " + a);
		System.out.println( "Unicode Vlaue of Character at Index position 10 = " + b);
		System.out.println( "Unicode Vlaue of Character at Index position 21 = " + c);
		System.out.println( "Unicode Vlaue of Character at Last Index position - 1 = " + d);
	}
}

OUTPUT

Java codePointBefore Method 1

ANALYSIS

First we declared the String variable and assigned a value using following statement

String str = "Learn Free Java Tutorial";

Following statements will find the Character at index position 0, 10, 21 and then assign the Unicode values of those character to the integer variables a, b and c.

int a = str.codePointBefore(1);
int b = str.codePointBefore(11);
int c = str.codePointBefore(22);

If you observe the above screenshot, str.codePointAt(11) is returning 32. This is because, we all know that character at index position 10 is Empty Space and according to ASCII Table, the Unicode value of Empty Space is 32.

NOTE: You should count the space as One Character.

In the next line we are using the Java length() function to calculate the string length.

int d = str.codePointBefore(str.length()- 1);

From the above code snippet you can observe that, we are subtracting one from string length because, length of a string will count from 1 to n where as index position will start from 0 and end’s at n – 1.

Following System.out.println statements will print the output

System.out.println( "Unicode Vlaue of Character at Index position 0 = " + a);
System.out.println( "Unicode Vlaue of Character at Index position 10 = " + b);
System.out.println( "Unicode Vlaue of Character at Index position 21 = " + c);
System.out.println( "Unicode Vlaue of Character at Last Index position - 1 = " + d);

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