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Classes and Objects in Java

Java Program to Convert Char to Int

Last Updated : 23 Apr, 2025

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Given a char value, and our task is to convert it into an int value in Java. We can convert a Character to its equivalent Integer in different ways, which are covered in this article.

Examples of Conversion from Char to Int:

Input : ch = ‘3’
Output : 3

Input : ch = ‘9’
Output : 9

The char data type is a single 16-bit Unicode character. Its value range lies between ‘\u0000’ (or 0) to ‘\uffff’ (or 65,535 inclusive). The char data type is used to store characters. So internally, the char values are stored as an ASCII value, for example, the character ‘a is stored as 97(Unicode value). So we can convert just by showing its Unicode value.

Methods to Convert Char to Int in Java

There are numerous approaches to the conversion of the Char datatype to the Integer (int) datatype. A few of them are listed below.

Using ASCII Values
Using String.valueOf() Method
Using Character.getNumericValue() Method

1. Using ASCII values

We can convert the char value to an int value using type casting (changing the data type from char to int ). This is the easiest way to convert the Character to an Integer value. Now we know that the if char ‘0’ is 48 so the ‘1’ would be 49 and so on so if we want to make it integer to we can convert it by actual number ‘3’-‘0′(51-48) = 3 (The actual value) so we can use this calculation to convert the value.

Example: Converting char to int using Typecasting in Java

Java

// Java Program to Convert Char to Int // Using ASCII value class Geeks  {     // Main driver method     public static void main(String[] args)     {         // Initializing a character         char num = '3';          // Printing the character value         System.out.println("char value: " + num);           // Converting character to its integer value         int n = num - '0';                   // Printing the integer value         System.out.println("int value: " + n);     } }

Output

char value: 3 char value: a int value: 97 int value: 3

2. Using the String.valueOf()

The method valueOf() of class String can convert various types of values to a String value. It can convert int, char, long, boolean, float, double, object, and char array to String, which can be converted to an int value by using the Integer.parseInt() method. The program below illustrates the use of the valueOf() method.

Example: Converting char to int using the method String.valueOf() in Java.

Java

// Java program to convert Char to Int // Using valueOf() method of String Class class Geeks {     // Main driver method     public static void main(String[] args)     {          // Declaring and initializing a character         char ch = '3';          // Printing the character value         System.out.println("char value: " + ch);          // Converting the character to it's integer value         // using valueOf() method         int a = Integer.parseInt(String.valueOf(ch));          // Printing the integral value         // corresponding to its character value         System.out.println("int value: " + a);     } }

Output

char value: 3 int value: 3

3. Using getNumericValue()

The getNumericValue() method present in the Character class is used to get the integer value of any specific character. For example, the character ‘1’ will return an int having a value of 1.

Example: Converting char to int using the method getNumericValue().

Java

// Java Program to Convert Character to Integer // Using getNumericValue() method of Character Class  // Driver Class class Geeks {     // Main driver method     public static void main(String[] args)     {         // Declaring and initializing a character         char ch = '3';          // Displaying above character on console         System.out.println("char value: " + ch);          // Converting the Character to it's int value         // using getNumericValue() method of Character Class         int a = Character.getNumericValue(ch);          // Printing the corresponding integral value         System.out.println("int value: " + a);     } }

Output

char value: 3 int value: 3

Classes and Objects in Java

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The Arrays.sort() method is used for sorting the elements in an Array. It has two main variations: Sorting the entire array (it may be an integer or character array) Sorting a specific range by passing the starting and ending indices.Below is a simple example that uses the sort() method to arrange a

6 min read
Java Program to Sort the Elements of an Array in Descending Order

Here, we will sort the array in descending order to arrange elements from largest to smallest. The simple solution is to use Collections.reverseOrder() method. Another way is sorting in ascending order and reversing. 1. Using Collections.reverseOrder()In this example, we will use Collections.reverse

2 min read
Java Program to Sort the Elements of an Array in Ascending Order

Here, we will sort the array in ascending order to arrange elements from smallest to largest, i.e., ascending order. So the easy solution is that we can use the Array.sort method. We can also sort the array using Bubble sort. 1. Using Arrays.sort() MethodIn this example, we will use the Arrays.sort(

2 min read
Remove duplicates from Sorted Array

Given a sorted array arr[] of size n, the goal is to rearrange the array so that all distinct elements appear at the beginning in sorted order. Additionally, return the length of this distinct sorted subarray. Note: The elements after the distinct ones can be in any order and hold any value, as they

7 min read
Java Program to Merge Two Arrays

Given two arrays, the task is to merge or concatenate them and store the result into another array. Example: [GFGTABS] Java // Java Program to demonstrate merging // two array using System.arraycopy() method import java.util.Arrays; public class MergeTwoArrays1 { public static void main(String[] arg

5 min read
Java Program to Check if two Arrays are Equal or not

In Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure. Example: In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arra

4 min read
Remove all Occurrences of an Element from Array in Java

In Java, removing all occurences of a given element from an array can be done using different approaches that are, Naive approach using array copyJava 8 StreamsUsing ArrayList.removeAll()Using List.removeIf()Problem Stament: Given an array and a key, the task is to remove all occurrences of the spec

5 min read
Java Program to Find Common Elements Between Two Arrays

Given two arrays and our task is to find their common elements. Examples:Input: Array1 = ["Article", "for", "Geeks", "for", "Geeks"], Array2 = ["Article", "Geeks", "Geeks"]Output: [Article, Geeks] Input: Array1 = ["a", "b", "c", "d", "e", "f"], Array2 = ["b", "d", "e", "h", "g", "c"]Output: [b, c, d

4 min read
Array Copy in Java

In Java, copying an array can be done in several ways, depending on our needs such as shallow copy or deep copy. In this article, we will learn different methods to copy arrays in Java. Example: Assigning one array to another is an incorrect approach to copying arrays. It only creates a reference to

6 min read
Java Program to Left Rotate the Elements of an Array

In Java, left rotation of an array involves shifting its elements to the left by a given number of positions, with the first elements moving around to the end. There are different ways to left rotate the elements of an array in Java. Example: We can use a temporary array to rotate the array left by

5 min read

Java 2-D Arrays (Matrix) Programs

Print a 2D Array or Matrix in Java

In this article, we will learn to Print 2 Dimensional Matrix. 2D-Matrix or Array is a combination of Multiple 1 Dimensional Arrays. In this article we cover different methods to print 2D Array. When we print each element of the 2D array we have to iterate each element so the minimum time complexity

4 min read
Java Program to Add two Matrices

Given two matrices A and B of the same size, the task is to add them in Java. Examples: Input: A[][] = {{1, 2}, {3, 4}} B[][] = {{1, 1}, {1, 1}} Output: {{2, 3}, {4, 5}} Input: A[][] = {{2, 4}, {3, 4}} B[][] = {{1, 2}, {1, 3}} Output: {{3, 6}, {4, 7}} Program to Add Two Matrices in JavaFollow the St

2 min read
Sorting a 2D Array according to values in any given column in Java

We are given a 2D array of order N X M and a column number K ( 1<=K<=m). Our task is to sort the 2D array according to values in Column K. Examples: Input: If our 2D array is given as (Order 4X4) 39 27 11 42 10 93 91 90 54 78 56 89 24 64 20 65 Sorting it by values in column 3 Output: 39 27 11

3 min read
Java Program to Check if two Arrays are Equal or not

In Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure. Example: In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arra

4 min read
Java Program to Find Transpose of Matrix

Transpose of a matrix is obtained by changing rows to columns and columns to rows. In other words, the transpose of A[ ][ ] is obtained by changing A[i][j] to A[j][i]. Example of First Transpose of MatrixInput: [ [ 1 , 2 , 3 ] , [ 4 , 5 , 6 ] , [ 7 , 8 , 9 ] ]Output: [ [ 1 , 4 , 7 ] , [ 2 , 5 , 8 ]

5 min read
Java Program to Find the Determinant of a Matrix

The determinant of a matrix is a special calculated value that can only be calculated if the matrix has same number of rows and columns (square matrix). It is helpful in determining the system of linear equations, image processing, and determining whether the matrix is singular or non-singular. In t

5 min read
Java Program to Find the Normal and Trace of a Matrix

For a given 2D matrix, the purpose is to find the Trace and Normal of the matrix. In this article, we will learn about Normal and Trace of a Matrix in Java. Examples : Input : matrix[][] = {{1, 4, 4}, {2, 3, 7}, {0, 5, 1}}; Output : Normal = 11 Trace = 5 Explanation : Normal = sqrt(1*1+ 4*4 + 4*4 +

3 min read
Java Program to Print Boundary Elements of the Matrix

Given a matrix of size Row x Col Print the boundary elements of the matrix. Boundary elements are those elements which are not surrounded by elements on all four directions, i.e. elements in the first row, first column, last row and last column. Example: Input : 1 2 3 4 5 6 7 8 9 Output: 1 2 3 4 6 7

2 min read
Java Program to Rotate Matrix Elements

A matrix is simply a two-dimensional array. So, the goal is to deal with fixed indices at which elements are present and to perform operations on indexes such that elements on the addressed should be swapped in such a manner that it should look out as the matrix is rotated. For a given matrix, the t

6 min read
Java Program to Compute the Sum of Diagonals of a Matrix

For a given 2D square matrix of size N*N, the task is to find the sum of elements in the Principal and Secondary diagonals. For example, analyze the following 4 Ã— 4 input matrix. a00 a01 a02 a03a10 a11 a12 a13a20 a21 a22 a23a30 a31 a32 a33 Example: Input 1 : 6 7 3 4 8 9 2 1 1 2 9 6 6 5 7 2Output 1 :

4 min read
Java Program to Interchange Elements of First and Last in a Matrix Across Rows

For a given 4 Ã— 4 matrix, the task is to interchange the elements of the first and last rows and then return the resultant matrix. Illustration: Input 1: 1 1 5 0 2 3 7 2 8 9 1 3 6 7 8 2 Output 1: 6 7 8 2 2 3 7 2 8 9 1 3 1 1 5 0 Input 2: 7 8 9 10 11 13 14 1 15 7 12 22 11 21 30 1 Output 2: 11 21 30 1

3 min read
Java Program to Interchange Elements of First and Last in a Matrix Across Columns

For a given 4 x 4 matrix, the task is to interchange the elements of the first and last columns and then return the resultant matrix. Example Test Case for the ProblemInput : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Output : 4 2 3 1 8 6 7 5 12 10 11 9 16 14 15 13 Implementation of Interchange Elements

2 min read

Java String Programs

Java Program to Get a Character from a String

Given a String str, the task is to get a specific character from that String at a specific index. Examples: Input: str = "Geeks", index = 2Output: eInput: str = "GeeksForGeeks", index = 5Output: F Below are various ways to do so: Using String.charAt() method: Get the string and the indexGet the spec

5 min read
Replace a character at a specific index in a String in Java

In Java, here we are given a string, the task is to replace a character at a specific index in this string. Examples of Replacing Characters in a StringInput: String = "Geeks Gor Geeks", index = 6, ch = 'F'Output: "Geeks For Geeks."Input: String = "Geeks", index = 0, ch = 'g'Output: "geeks"Methods t

3 min read
Reverse a String in Java

In Java, reversing a string means reordering the string characters from the last to the first position. Reversing a string is a common task in many Java applications and can be achieved using different approaches. In this article, we will discuss multiple approaches to reverse a string in Java with

7 min read
Java Program to Reverse a String using Stack

The Stack is a linear data structure that follows the LIFO(Last In First Out) principle, i.e, the element inserted at the last is the element to come out first. Approach: Push the character one by one into the Stack of datatype character.Pop the character one by one from the Stack until the stack be

2 min read
Sort a String in Java (2 different ways)

The string class doesn't have any method that directly sorts a string, but we can sort a string by applying other methods one after another. The string is a sequence of characters. In java, objects of String are immutable which means a constant and cannot be changed once created. Creating a String T

6 min read
Swapping Pairs of Characters in a String in Java

Given string str, the task is to write a Java program to swap the pairs of characters of a string. If the string contains an odd number of characters then the last character remains as it is. Examples: Input: str = â€œJavaâ€Output: aJav Explanation: The given string contains even number of characters.

3 min read
Check if a given string is Pangram in Java

Given string str, the task is to write Java Program check whether the given string is a pangram or not. A string is a pangram string if it contains all the character of the alphabets ignoring the case of the alphabets. Examples: Input: str = "Abcdefghijklmnopqrstuvwxyz"Output: YesExplanation: The gi

3 min read
Print first letter of each word in a string using regex

Given a string, extract the first letter of each word in it. "Words" are defined as contiguous strings of alphabetic characters i.e. any upper or lower case characters a-z or A-Z. Examples: Input : Geeks for geeksOutput :Gfg Input : United KingdomOutput : UKBelow is the Regular expression to extract

3 min read
Java Program to Determine the Unicode Code Point at Given Index in String

ASCII is a code that converts the English alphabets to numerics as numeric can convert to the assembly language which our computer understands. For that, we have assigned a number against each character ranging from 0 to 127. Alphabets are case-sensitive lowercase and uppercase are treated different

5 min read
Remove Leading Zeros From String in Java

Given a string of digits, remove leading zeros from it. Illustrations: Input : 00000123569Output: 123569 Input: 000012356090Output: 12356090 Approach: We use the StringBuffer class as Strings are immutable. Count leading zeros by iterating string using charAt(i) and checking for 0 at the "i" th indi

3 min read
Compare two Strings in Java

String in Java are immutable sequences of characters. Comparing strings is the most common task in different scenarios such as input validation or searching algorithms. In this article, we will learn multiple ways to compare two strings in Java with simple examples. Example: To compare two strings i

4 min read
Compare two strings lexicographically in Java

In this article, we will discuss how we can compare two strings lexicographically in Java. One solution is to use Java compareTo() method. The method compareTo() is used for comparing two strings lexicographically in Java. Each character of both the strings is converted into a Unicode value for comp

3 min read
Java program to print Even length words in a String

Given a string s, write a Java program to print all words with even length in the given string. Example to print even length words in a String Input: s = "i am Geeks for Geeks and a Geek" Output: am Geek Example: [GFGTABS] Java // Java program to print // even length words in a string class GfG { pu

3 min read
Insert a String into another String in Java

Given a String, the task is to insert another string in between the given String at a particular specified index in Java. Examples: Input: originalString = "GeeksGeeks", stringToBeInserted = "For", index = 4 Output: "GeeksForGeeks" Input: originalString = "Computer Portal", stringToBeInserted = "Sci

4 min read
Split a String into a Number of Substrings in Java

Given a String, the task it to split the String into a number of substrings. A String in java can be of 0 or more characters. Examples : (a) "" is a String in java with 0 character (b) "d" is a String in java with 1 character (c) "This is a sentence." is a string with 19 characters. Substring: A Str

5 min read

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