User Define structure and nested structure.

Define structure and nested structure. Write a program to find out whether the nth term of the Fibonacci series is a prime number or not. Read the value of n from the user and display the result in the main function. Uses separate user-defined function to generate the nth Fibonacci term and to check whether that number is prime or not.

 

1. Structure: A structure is a user-defined data type in C that allows you to combine different data types to define a single type. For example:

struct Person {
    char name[50];
    int age;
    float height;
};

Here, struct Person is the structure name, and name, age, and height are its members.

2. Nested Structure: A nested structure is a structure that is a member of another structure. For example:

struct Address {
    char city[50];
    char street[50];
};

struct Person {
    char name[50];
    int age;
    struct Address address;
};

Here, struct Address is nested within struct Person.

Now, let's write a program to find out whether the nth term of the Fibonacci series is a prime number or not:

#include <stdio.h>

// Function to generate the nth Fibonacci term
int fibonacci(int n) {
    if (n <= 1)
        return n;
    else
        return fibonacci(n - 1) + fibonacci(n - 2);
}

// Function to check whether a number is prime
int isPrime(int num) {
    if (num <= 1)
        return 0; // Not prime

    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0)
            return 0; // Not prime
    }

    return 1; // Prime
}

int main() {
    int n, fib;

    // Input value of n
    printf("Enter the value of n: ");
    scanf("%d", &n);

    // Generate the nth Fibonacci term
    fib = fibonacci(n);

    // Check whether the nth Fibonacci term is prime or not
    if (isPrime(fib))
        printf("%dth Fibonacci term (%d) is a prime number.\n", n, fib);
    else
        printf("%dth Fibonacci term (%d) is not a prime number.\n", n, fib);

    return 0;
}

This program defines two functions: fibonacci() to generate the nth Fibonacci term and isPrime() to check whether a number is prime. Then, it takes input for the value of n from the user, generates the nth Fibonacci term, checks if it's prime or not, and displays the result.