Functions and recrusion.

1.Write a program using functions to find the average of three numbers.

#include<stdio.h>

float average (int a,int b,int c);

int main(){

    int a,b,c;

    printf("Enter the value of a");

    scanf("%d", &a);

    printf("Enter the value of b");

    scanf("%d", &b);

    printf("Enter the value of c");

    scanf("%d", &c);

    printf("The average is %f", average(a,b,c));

}

float average (int a,int b,int c){

    float res;

    res=(a+b+c)/3;

    return res;

}

2.Write a function to convert Celcius temperature into Fahrenheit.

#include<stdio.h>

float far(float a);

int main(){

    float a;

    printf("Enter the Temparature in celsius:");

    scanf("%f", &a);

    printf("The temprature in Farenheit:%f", far(a));

}

float far(float a){

    float b;

    b=((a*9)/5)+32;

    return b;

}

3.Write a function to calculate the force of attraction on a body of mass m exerted by earth. (g=9.8m/S2)

#include<stdio.h>

float force(float m);

int main(){

    float m;

    printf("Enter the Mass of the object:");

    scanf("%f", &m);

    printf("force of attraction is %fN.",

                     force(m));

}

float force(float m){

    float a;

    a=m*9.8;

    return a;

}

4.Write a program using recursion to calculate the nth element of the Fibonacci series.

#include <stdio.h>

int fibonacci(int n) {

    if (n <= 0) {

        return 0;

    } else if (n == 1) {

        return 1;

    } else {

        return fibonacci(n - 1) + fibonacci(n - 2);

    }

}

int main() {

    int n;

    printf("Enter the value of n: ");

    scanf("%d", &n);

    if (n < 0) {

        printf("Invalid input. n should be a

                non-negative integer.\n");

    } else {

        int result = fibonacci(n);

        printf("The %dth element of the Fibonacci

                 series is: %d\n", n, result);

    }

    return 0;

}

5.Write a recursive function to calculate the sum of first n natural numbers.

#include <stdio.h>

int sumOfNaturals(int n) {

    if (n <= 0) {

        return 0; // Base case: Sum of 0 natural

`                     numbers is 0

    } else {

        return n + sumOfNaturals(n - 1);

// Recursive case: Sum of n naturals =

        n + sum of (n-1) naturals

    }

}

int main() {

    int n;

    printf("Enter a positive integer n: ");

    scanf("%d", &n);

    if (n < 0) {

        printf("Invalid input. n should be

                 a positive integer.\n");

    } else {

        int result = sumOfNaturals(n);

        printf("The sum of the first %d

                natural numbers is: %d\n", n, result);

    }

    return 0;

}

6.Write a program using functions to print the following pattern(first n lines):

*

***

*****

#include <stdio.h>
void printPattern(int n) {
    for (int i = 1; i <= n; i++) {
        // Print '*' for odd line numbers
        if (i % 2 == 1) {
            for (int j = 1; j <= i; j++) {
                printf("*");
            }
        }
        // Print a new line after each line
        printf("\n");
    }
}
int main() {
    int n;
    printf("Enter the number of lines: ");
    scanf("%d", &n);
    if (n < 1) {
        printf("Invalid input. Please enter a 
                positive integer.\n");
    } else {
        printPattern(n);
    }
    return 0;
}