Compilation error with bresenham line algorithm?

Question

#include 
#include 
#include 

int x0,y0,xn,yn;

void bresenham(void)
{
    int dx,dy,m,pk,xk,yk,k;
    glClear(GL_COLOR_BU         


        

Answer 1

why it is showing y0 &yn are redeclared as different kind of symbol

Because you are:

The y0(), y1(), and yn() functions shall compute Bessel functions of x of the second kind of orders 0, 1, and n, respectively.

Switch to different names or don't #include <math.h>.