Thread: program doesnt enter function

hello everyone, i wrote a code in C that suppose to calculate COS of an angle.
i dont need help with the writing, i just have one problem, for some reason the program doesnt enter the function cosApprox, it suppose to enter the function and save the result in sum_column , but it just skips it, does someone knows why?

Thanks.

Code:

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

#define PI 3.1415927

double power(double a, int b);

long factorial(int n);

double cosElement(double x, int i);

double cosApprox(double x, int i);

int main()
{
	 double x;  /* Angle variable */
	 int k;     /* Number of elements variable */
	 double sum_column; /* Sum of all elements variable */

	 clrscr();

	 printf("\nEnter an angle (in Radians):");
	 scanf("%lf", &x);
	 printf("\nEnter number of elements:");
	 scanf("%d", &k);
	 while(k<0)
	 {
		printf("Erroneous Input. Please enter number of elements (k>=0):");
		scanf("%d", &k);
	 }

	 sum_column=cosApprox(x, k); /* a function to calculate the sum of elements */

	 printf("The value of Cos(x) is: %.4lf", 1+sum_column);

	 getch();
	 return 0;
}
	 double cosApprox(double x, int i)
	 {
		 double sum=0;

		 for(i=i;i>0;i--)
		 {

			 sum=sum+cosElement(x, i);
		 }
		 return sum;
	 }
	 double cosElement(double x, int i) /* a function to calculate the element in the i place of the column */
{
	 double element;
	 element=pow((-1),i)*power(x,i)/factorial(i);

	 return element;
}


	 long factorial(int n)  /* a function to calculate the factorial of a number */
{
	 long sum_f=2*n;
	 int i;

	 for(i=2*n;i>1;i--)
	 {
		 sum_f=sum_f*(2*n-1);
	 }
	 return sum_f;
}

	 double power(double a, int b) /* a function to calculate x^2k */
{
	 double power;

	 power=pow(a,2*b);

	 return power;
}