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Check Frequency of Characters in a string
Finding the frequency of a character in a string, means we have to check how many times a particular character is present in that string. Here, we have coded a Java Program for the same. Let’s take an example of a string “prepinsta” . In which we have to check that how many times each of the characters gets repeated in the string.


Algorithm
- Take string input from user and store it in the variable called “str”.
- After that make freq array having size of length of string.
- Convert string to char array .
- Run for loop start from i=0 to str<length() store 1 to freq array.
- Run j loop start from i=i+1 to j<str.length().
- check condition if(string[i] == string[j]) then do freq[i]++ and set string[j]=’0′ .
- After that display frequency of character one by one.
Code in Java (Check Frequency of Characters)
import java.util.Scanner; public class FrequencyOfCharactersInAString { public static void main(String[] args) { Scanner sc =new Scanner(System.in); System.out.print("Enter String : "); String str = sc.nextLine(); int[] freq = new int[str.length()]; int i, j; //Converts given string into character array char string[] = str.toCharArray(); for(i = 0; i <str.length(); i++) { freq[i] = 1; for(j = i+1; j <str.length(); j++) { if(string[i] == string[j]) { freq[i]++; //Set string[j] to 0 to avoid printing visited character string[j] = '0'; } } } //Displays the each character and their corresponding frequency System.out.println("Characters and their corresponding frequencies"); for(i = 0; i <freq.length; i++) { if(string[i] != ' ' && string[i] != '0') System.out.println(string[i] + "-" + freq[i]); } } }
Output
Enter String : prepinsta
Characters and their corresponding frequencies
p-2
r-1
e-1
i-1
n-1
s-1
t-1
a-1
import java.util.*;
public class Main
{
public static void main(String[] args) {
String s=”prepinsta”;
Mapmap=new HashMap();
for(int i=0;i
“+entry.getValue()+” “);}
}
}