## Fibonacci: Using fork() in the Child Process

The Fibonacci sequence is a famous mathematical series that has captured the interest of mathematicians and programmers alike. It is defined as a sequence of numbers where each number is the sum of the two preceding ones, starting with 0 and 1. This sequence has been studied and used in various fields, including computer science. In this article, we will explore how fork() can be used in the child process to generate the Fibonacci sequence.

Before we dive into the details, let's first understand what fork() is. In simple terms, fork() is a system call that creates a copy of the current process, called the child process. The child process has its own memory space and runs independently of the parent process. This feature of fork() makes it a powerful tool for creating parallel processes.

Now, let's see how we can use fork() to generate the Fibonacci sequence in the child process. We will be using the C programming language for this example.

First, we need to include the necessary header files, which are "stdio.h" for input and output operations and "unistd.h" for fork().

## <code><pre>#include <stdio.h>

## #include <unistd.h>

## </pre></code>

Next, we need to define a function that will calculate the Fibonacci sequence. Let's name it "fibonacci" and pass the number of terms as a parameter.

## <code><pre>void fibonacci(int num) {

## int first = 0, second = 1, next, i;

## printf("Fibonacci Series: ");

## for (i = 0; i < num; i++) {

## printf("%d ", first);

## next = first + second;

## first = second;

## second = next;

## }

## printf("\n");

## }

## </pre></code>

In this function, we initialized the first two numbers of the sequence, which are 0 and 1. Then, we used a for loop to calculate and print the next number in the sequence. After each iteration, we updated the values of the first and second numbers to continue the sequence.

Now, we can use fork() to create a child process and call the fibonacci() function in it.

## <code><pre>int main() {

## int num;

## printf("Enter the number of terms: ");

## scanf("%d", &num);

## //creating a child process

## pid_t pid = fork();

## if (pid == 0) { //child process

## printf("Child Process:\n");

## fibonacci(num);

## } else if (pid > 0) { //parent process

## wait(NULL); //wait for child process to finish

## printf("Parent Process:\n");

## fibonacci(num);

## } else { //fork failed

## printf("Fork failed\n");

## }

## return 0;

## }

## </pre></code>

In the above code, we first ask the user to enter the number of terms they want to generate. Then, we use fork() to create a child process. In the child process, we print a message to differentiate it from the parent process, and then we call the fibonacci() function. In the parent process, we use the wait() function to wait for the child process to finish before calling the fibonacci() function.

Now, let's see the output of this program for the input of 7 terms.

## <code><pre>Enter the number of terms: 7

## Child Process:

## Fibonacci Series: 0 1 1 2 3 5 8

## Parent Process:

## Fibonacci Series: 0 1 1 2 3 5 8

## </pre></code>

As we can see, both the child and parent processes have generated the same Fibonacci sequence. This is because fork() created a copy of the parent process, and the fibonacci() function was called in both processes.

In conclusion, using fork() in the child process can be an efficient way to generate the Fibonacci sequence. This technique can also be applied to other mathematical or computational tasks that require parallel processing. So, the next time you come across the Fibonacci sequence, you can use this approach to impress your peers with your knowledge of fork() in the child process.