Multiple calculations in 4 processes using fork()

Last Updated : 06 Mar, 2024

Write a program to create 4 processes: parent process and its child process which perform various tasks :

Parent process count the frequency of a number
1st child sort the array
2nd child find total even number(s) in a given array
3rd child calculate the sum of even numbers in an array

Example -

Input :  
2, 4, 6, 7, 9, 0, 1, 5, 8, 3
Output : 
Parent process :
the key to be searched is 7
the frequency of 7 is 1
1st child process :
the sorted array is
0 1 2 3 4 5 6 7 8 9 
2nd child process :
 Total even no are: 5 
3rd child process :
the sum is :45

Explanation -

Here, we had used fork() function to create 4 processes three child and one parent process. So, here we use two fork() function which create 4 process n1=fork() and n2 = fork()

if n1 and n2 is greater than zero then it is parent process which counts the frequency of a number.
if n1 is equal to zero and n2 is greater than zero then it is 1st child process which sorts the given array.
if n1 is greater than zero and n2 is equal to zero than it is 2nd child process which finds the total even numbers in the array.
if n1 and n2 both equal to zero then it is 3rd child calculates the sum of all elements in an array.

Code -

CPP

// C++ code to demonstrate the calculation
// in parent and its 3 child processes using fork()
#include <iostream>
#include <unistd.h>

using namespace std;

int main()
{

    int a[10] = { 2, 4, 6, 7, 9, 0, 1, 5, 8, 3 };
    int n1, n2, i, j, key, c, temp;
    n1 = fork();
    n2 = fork();

    // if n1 is greater than zero
    // and n2 is greater than zero
    // then parent process executes
    if (n1 > 0 && n2 > 0) {

        int c = 0;
        cout << "Parent process :" << endl;

        // key to be searched is 7
        key = 7;
        cout << "the key to be searched is " << key << endl;

        for (i = 0; i < 10; i++) {

            if (a[i] == key)
                // frequency of key
                c++;
        }

        cout << "the frequency of " << key << " is " << c << endl;
    }

    // else if n1 is zero
    // and n2 is greater than zero
    // then 1st child process executes
    else if (n1 == 0 && n2 > 0) {

        cout << "1st child process :" << endl;

        for (i = 0; i < 10; i++) {

            for (j = 0; j < 9; j++) {

                if (a[j] > a[j + 1]) {

                    temp = a[j];
                    a[j] = a[j + 1];
                    a[j + 1] = temp;
                }
            }
        }

        cout << "the sorted array is" << endl;

        for (i = 0; i < 10; i++) {

            cout << a[i] << " ";
        }

        cout << endl;
    }

    // else if n1 is greater than zero
    // and n2 is zero
    // then 2nd child process executes
    else if (n1 > 0 && n2 == 0) {

        int f = 0;
        cout << "2nd child process :" << endl;

        for (i = 0; i < 10; i++) {

            // counting total even numbers
            if (a[i] % 2 == 0) {

                f++;
            }
        }

        cout << " Total even no are: " << f << " ";
        cout << endl;
    }

    // else if n1 is zero
    // and n2 is zero
    // then 3rd child process executes
    else if (n1 == 0 && n2 == 0) {

        cout << "3rd child process :" << endl;

        int sum = 0;
        // summing all given keys
        for (i = 0; i < 10; i++) {

            sum = sum + a[i];
        }

        cout << "the sum is :" << sum << endl;
    }

    return 0;
}

Java

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        // The array to be used in the calculations
        int[] a = {2, 4, 6, 7, 9, 0, 1, 5, 8, 3};

        // Parent process
        System.out.println("Parent process :");

        // Key to be searched is 7
        int key = 7;
        System.out.println("The key to be searched is " + key);

        // Frequency of key
        int c = 0;
        for (int num : a) {
            if (num == key) {
                c++;
            }
        }
        System.out.println("The frequency of " + key + " is " + c);

        // 1st child process
        System.out.println("1st child process :");

        // Sorting the array
        Arrays.sort(a);
        System.out.println("The sorted array is " + Arrays.toString(a));

        // 2nd child process
        System.out.println("2nd child process :");

        // Counting total even numbers
        int f = 0;
        for (int num : a) {
            if (num % 2 == 0) {
                f++;
            }
        }
        System.out.println("Total even numbers are: " + f);

        // 3rd child process
        System.out.println("3rd child process :");

        // Summing all given keys
        int sum = 0;
        for (int num : a) {
            sum += num;
        }
        System.out.println("The sum is : " + sum);
    }
}

using System;
using System.Threading.Tasks;

class Program
{
    static void Main()
    {
        int[] a = { 2, 4, 6, 7, 9, 0, 1, 5, 8, 3 };

        // Fork process
        int n1 = 0;
        int n2 = 0;

        // Creating tasks for child processes
        Task firstChild = Task.Run(() =>
        {
            Console.WriteLine("1st child process :");

            // Sorting the array
            Array.Sort(a);

            Console.WriteLine("The sorted array is " + string.Join(", ", a));
        });

        Task secondChild = Task.Run(() =>
        {
            Console.WriteLine("2nd child process :");

            // Counting total even numbers
            int f = 0;
            foreach (int num in a)
            {
                if (num % 2 == 0)
                    f++;
            }

            Console.WriteLine("Total even numbers are: " + f);
        });

        // Parent process
        Console.WriteLine("Parent process :");

        // Key to be searched
        int key = 7;
        Console.WriteLine("The key to be searched is " + key);

        // Frequency of key
        int c = 0;
        foreach (int num in a)
        {
            if (num == key)
                c++;
        }

        Console.WriteLine("The frequency of " + key + " is " + c);

        Task thirdChild = Task.Run(() =>
        {
            Console.WriteLine("3rd child process :");

            // Summing all given keys
            int sum = 0;
            foreach (int num in a)
            {
                sum += num;
            }

            Console.WriteLine("The sum is : " + sum);
        });

        // Wait for all tasks to complete before exiting
        Task.WaitAll(firstChild, secondChild, thirdChild);
    }
}

JavaScript

// The array to be used in the calculations
let a = [2, 4, 6, 7, 9, 0, 1, 5, 8, 3];

// Parent process
console.log("Parent process :");

// Key to be searched is 7
let key = 7;
console.log("The key to be searched is " + key);

// Frequency of key
let c = 0;
for (let num of a) {
    if (num === key) {
        c++;
    }
}
console.log("The frequency of " + key + " is " + c);

// 1st child process
console.log("1st child process :");

// Sorting the array
a.sort((x, y) => x - y);
console.log("The sorted array is " + JSON.stringify(a));

// 2nd child process
console.log("2nd child process :");

// Counting total even numbers
let f = 0;
for (let num of a) {
    if (num % 2 === 0) {
        f++;
    }
}
console.log("Total even numbers are: " + f);

// 3rd child process
console.log("3rd child process :");

// Summing all given keys
let sum = 0;
for (let num of a) {
    sum += num;
}
console.log("The sum is : " + sum);

Python3

# Importing the required libraries
import os

# The array to be used in the calculations
a = [2, 4, 6, 7, 9, 0, 1, 5, 8, 3]

# Creating the first child process
n1 = os.fork()

# Creating the second child process
n2 = os.fork()

# If n1 is greater than zero and n2 is greater than zero
# then parent process executes
if n1 > 0 and n2 > 0:
    print("Parent process :")

    # Key to be searched is 7
    key = 7
    print("The key to be searched is", key)

    # Frequency of key
    c = a.count(key)

    print("The frequency of", key, "is", c)

# Else if n1 is zero and n2 is greater than zero
# then 1st child process executes
elif n1 == 0 and n2 > 0:
    print("1st child process :")

    # Sorting the array
    a.sort()

    print("The sorted array is", a)

# Else if n1 is greater than zero and n2 is zero
# then 2nd child process executes
elif n1 > 0 and n2 == 0:
    print("2nd child process :")

    # Counting total even numbers
    f = len([num for num in a if num % 2 == 0])

    print("Total even numbers are:", f)

# Else if n1 is zero and n2 is zero
# then 3rd child process executes
elif n1 == 0 and n2 == 0:
    print("3rd child process :")

    # Summing all given keys
    sum = sum(a)

    print("The sum is :", sum)

Output -

Parent process :
the key to be searched is 7
the frequency of 7 is 1
1st child process :
the sorted array is
0 1 2 3 4 5 6 7 8 9 
2nd child process :
 Total even no are: 5 
3rd child process :
the sum is :45

Analysis of Algorithms

Shivani Baghel 1

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Multiple calculations in 4 processes using fork()

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