# Java program to check frequency of characters in a string

## 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 : prepinstaCharacters and their corresponding frequenciesp-2r-1e-1i-1n-1s-1t-1a-1`

### One comment on “Java program to check frequency of characters in a string”

• Mahesh

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()+” “);
}
}
}