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Java codePointCount Method

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The Java codePointCount method is one of the Java String Method which is used to count number of Unicode points within the specified text range.

In this article we will show you, How to use codePointCount in Java Programming language with example.

Java codePointCount method syntax

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

public int codePointCount(int Starting_Index, int End_Index) 

//In order to use in program
String_Object.codePointCount(int Starting_Index, int End_Index)
  • String_Object: Please specify the valid String Object.
  • Starting_Index: Please specify the index position of a first character.
  • End_Index: Please specify the index position of a last but one character.

Return Value

The Java codePointCount Function will count no of Unicode points from Starting_Index to End_Index – 1. Mathematically we say the return value as (End_Index – Starting_Index).

For example, codePointCount(12, 20) will return 8 as an output because 20 – 12 = 8. If we provide the Index position out of range or negative value, then codePointCount Function will throw an error.

Java codePointCount Example

The Java string codePointCount method is used to count the Unicode points between specified range. In this Java program, We are going to find the same.

package StringFunctions;

public class CodePointCount {
	public static void main(String[] args) {
		String str = "Learn Free Java Tutorial";
		
		int a = str.codePointCount(0, 3);
		int b = str.codePointCount(4, 11);
		int c = str.codePointCount(12, str.length()- 1);
		int d = str.codePointCount(0, str.length()- 1);
		
		System.out.println( "Total Unicode Points from 0 to Index position 3 = " + a);
		System.out.println( "Total Unicode Points from 4 to Index position 11 = " + b);
		System.out.println( "Total Unicode Points from 12 to Last Index position = " + c);
		System.out.println( "Total Unicode Points from 0 to Last Index position = " + d);
	}
}

OUTPUT

Java codePointCount Method 1

ANALYSIS

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

String str = "Learn Free Java Tutorial";

Within the following Java codePointCount statements, first statement will find the Count the Unicode points between 0 and 3 and the other will find Unicode points between 4 and 11

at index position 0, 8, 14 and then assign the Unicode values of those character to the integer variables a, b and c.

int a = str.codePointCount(0, 3);
int b = str.codePointCount(4, 11);

If you observe the above screenshot, str.codePointCount(0, 3) is returning 3. This is because, there are three Unicode points between 0 and 3 or (3 – 0 = 3).

NOTE: You should count the space as One Character.

Within the next two lines we are using the Java codePointCount method along with the string length function to calculate the string length.

int c = str.codePointCount(12, str.length()- 1);
int d = str.codePointCount(0, 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( "Total Unicode Points from 0 to Index position 3 = " + a);
System.out.println( "Total Unicode Points from 4 to Index position 11 = " + b);
System.out.println( "Total Unicode Points from 12 to Last Index position = " + c);
System.out.println( "Total Unicode Points from 0 to Last Index position = " + d);

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