#include <stdio.h>
#include <string.h>
#include <math.h>
 
/* f = g + h; n is the max degree of f, g, and h */
 
void add(double f[], double g[], double h[], int n);
 
#define N 1000
 
int main ()
{
	double poly1[N], poly2[N], solution[N];
	int degree = 0;
 
	add(poly1, poly2, solution, degree);
}
 
void add(double f[], double g[], double h[], int n)
{
	int i, degree;
 
	printf("Enter the degree of your polynomials: ");
	scanf_s("%d", &n);
	i = n;
	degree = i;
 
	while(0 <= n)
	{
		printf("\nEnter the coefficient for polynomial 1 of x^%d: ", n);
		scanf_s("%lf", &g[n]);
		n--;
	}
	while(0 <= i)
	{
		printf("\nEnter the coefficient for polynomial 2 of x^%d: ", i);
		scanf_s("%lf", &h[n]);
		i--;
	}
	while(0 <= degree)
	{
		if(degree == 0)
		{
			f[degree] = g[degree] + h[degree];
			printf("%lf\n", f[degree]);
		}
		else
		{
			f[degree] = g[degree] + h[degree];
			printf("%lf*x^%d + \n", f[degree], degree);
		}
		degree--;
	}
}

SIMPLE PROGRAM FLOW EXAMPLE
 
"main"  -- gets the input from user as to how many degrees
        -- get each of the coefficients for all three polynomials.
        -- pass this info into the function "add"
 
"add"   -- add the same-degree coefficients together of each polynomial
        -- return the results back to "main"
 
"main"  -- format and print the results