Introduction
The Java codePointAt() method is a part of the Character class. It returns the Unicode code point of the character at the specified index in a char array. This lab will guide you through the process of using the codePointAt() method in Java.
Create a char array
In this step, we will create a char array to work with.
char[] arr = {'h', 'e', 'l', 'l', 'o'};
Get the code point at an index
In this step, we will use the codePointAt() method to get the code point of the character at a specific index in the char array.
int index = 2; // index of the third element (l)
int codepoint = Character.codePointAt(arr, index);
System.out.println("Code point at index " + index + " is " + codepoint);
Get the code point at an index within a limit
In this step, we will use the codePointAt() method with a limit parameter to get the code point of the character at a specific index in the char array within a certain limit.
int startIndex = 1; // start at index 1 (e)
int limitIndex = 3; // stop at index 3 (first l)
int codepoint2 = Character.codePointAt(arr, startIndex, limitIndex);
System.out.println("Code point at index " + startIndex + " within limit " + limitIndex + " is " + codepoint2);
Create a user input example
In this step, we will create a user input example that allows the user to enter a char array, an index, and a limit, and displays the code point of the character at the given index within the limit.
Scanner scanner = new Scanner(System.in);
System.out.print("Enter char array: ");
String input = scanner.nextLine();
char[] arr2 = input.toCharArray();
System.out.print("Enter index: ");
int index2 = scanner.nextInt();
System.out.print("Enter limit: ");
int limit2 = scanner.nextInt();
int codepoint3 = Character.codePointAt(arr2, index2, limit2);
System.out.println("Code point at index " + index2 + " within limit " + limit2 + " is " + codepoint3);
Compile and run the code
In this step, we will compile the CharCodepoint.java file and run it in the terminal.
Compile the code using the following command:
javac CharCodepoint.java
Run the code using the following command:
java CharCodepoint
The output should look like the following example:
Code point at index 2 is 108
Code point at index 1 within limit 3 is 101
Enter char array: world
Enter index: 3
Enter limit: 5
Code point at index 3 within limit 5 is 100
Summary
In this lab, we learned how to use the Java codePointAt() method to get the Unicode code point of a character at a specific index of a char array. We also learned how to use the codePointAt() method with a limit to obtain the code point of a character within a specified range. Finally, we created a user input example to practice using the method with dynamic data.
