Simpson(1_3)

#include <stdio.h>
#include <math.h>

// Function to calculate f(x)
float func(float x)
{
	return log(x);
}

// Function for approximate integral
float simpsons(float ll, float ul, int n)
{
	// Calculating the value of h
	float h = (ul - ll) / n;
        printf("Value of h: %f\n", h);

	// Calculating result
	float res = func(ll) + func(ul);
	for(int i = 1; i < n; i++)
	{
		if(i % 2 == 0)
			res = res + 2 * func(ll+i*h);
		else
			res = res + 4 * func(ll+i*h);
	}
	res = res * (h / 3);
	return res;
}

int main()
{
    float lower_limit, upper_limit;
    int n; // Number of interval
    printf("Enter the lower limit and upper limit: ");
    scanf("%f %f", &lower_limit, &upper_limit);

    printf("Enter the number of intervals: ");
    scanf("%d", &n);

    printf("The result is: %f\n", simpsons(lower_limit, upper_limit, n));

    return 0;
}