In this tutorial, we will create a Java program that will find the occurrence of a character in a String.

Program to find the occurrence of a character in a string

The purpose of this program is to find the occurrence of each character in a String. To begin, we will create an array of size 256 (ASCII upper range), with the goal of storing the occurrence count against the ASCII value of that character. For example, the occurrence of ‘A’ is stored in counter[65] because the ASCII value of A is 65; similarly, occurrences of other characters are stored in counter[65] against their ASCII index values.

• We then create another array to hold the characters of the given String, compare them with the characters in the String, and display the count of that particular char using the counter array when a match is found.

class JavaExample {  

   static void countEachChar(String str) 
   { 
	//ASCII values ranges upto 256
	int counter[] = new int[256]; 

	//String length
	int len = str.length(); 

	/* This array holds the occurrence of each char, For example
	 * ASCII value of A is 65 so if A is found twice then 
	 * counter[65] would have the value 2, here 65 is the ASCII value
	 * of A
	 */
	for (int i = 0; i < len; i++) 
		counter[str.charAt(i)]++; 

	// We are creating another array with the size of String
	char array[] = new char[str.length()]; 
        for (int i = 0; i < len; i++) { 
	   array[i] = str.charAt(i); 
	   int flag = 0; 
	   for (int j = 0; j <= i; j++) { 

		/* If a char is found in String then set the flag 
		 * so that we can print the occurrence
		 */
		if (str.charAt(i) == array[j])  
			flag++;                 
	   } 

	   if (flag == 1)  
	      System.out.println("Occurrence of char " + str.charAt(i)
		 + " in the String is:" + counter[str.charAt(i)]);             
	} 
   } 
   public static void main(String[] args) 
   {  
	String str = "developersdome"; 
	countEachChar(str); 
   } 
}

Output:

• Occurrence of char d in the strings: 2
• Occurrence of char e in the strings: 4
• Occurrence of char v in the strings: 1
• Occurrence of char l in the strings: 1
• Occurrence of char o in the strings: 2
• Occurrence of char p in the strings: 1
• Occurrence of char r in the strings: 1
• Occurrence of char s in the strings: 1
• Occurrence of char m in the strings: 1

In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing.In Java, encapsulation is a mechanism for combining variables (data) and methods (code) into a single unit. It is the process of concealing information details and safeguarding the object’s data and behavior. It’s one of the four key concepts in OOP. Because the encapsulating class is simple to test, it’s ideal for unit testing. find the occurrence of a character find the occurrence of a character find the occurrence of a character find the occurrence of a character find the occurrence of a character find the occurrence of a character find the occurrence of a character find the occurrence of a character