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Kotlin program to count the occurrences of each character in a string

Kotlin | Counting occurrences of each character: Here, we are going to learn how to count the occurrences of each character in a given string in Kotlin programming language?
Submitted by IncludeHelp, on April 29, 2020

Given a string, we have to count the occurrences of each character.

Example:

    Input:
    string = "Hello includehelp how are you !!"

    Output:
    { =5, a=1, !=2, c=1, d=1, e=4, H=1, h=2, i=1, l=4, n=1, o=3, p=1, r=1, u=2, w=1, y=1}

Program to count the occurrences of each character in a string in Kotlin

In this program, we are using the concept of HashMap, which will contain the individual characters along with its occurrences in the string.

package com.includehelp.basic

import java.util.*

//Main Function, entry Point of Program
fun main(args: Array<String>) {

    //Input Stream
    val sc = Scanner(System.`in`)

    //input April20.string value
    println("Input String : ")
    val str: String = sc.nextLine()

    val characterHashMap: HashMap<Char, Int> = HashMap<Char, Int>()
    var c: Char
    // Scan string and build hash table
    for(i in str.indices){
        c = str[i]
        if (characterHashMap.containsKey(c)) {
            // increment count corresponding to c
            characterHashMap[c] = characterHashMap[c]!!+1

        } else {
            characterHashMap[c] = 1
        }
    }

    //print All Occurrence of character
    println("All character Count: $characterHashMap")
}

Output

Run 1:
Input String :
Hello includehelp how are you !!
All character Count: { =5, a=1, !=2, c=1, d=1, e=4, H=1, h=2, i=1, l=4, n=1, o=3, p=1, r=1, u=2, w=1, y=1}
---
Run 2:
Input String :
Hindustan India android Kotlin Java Flutter
All character Count: { =5, a=5, d=4, e=1, F=1, H=1, i=4, I=1, J=1, K=1, l=2, n=5, o=2, r=2, s=1, t=4, u=2, v=1}