[C語言]DDA畫線算法與TC2.0系統函數line（）的效率比較

include <time.h>
#include <graphics.h>

void dda_line(int xa,int ya,int xb,int yb,int c)
{
  float delta_x,delta_y,x,y;
  int dx,dy,steps,k;
  dx=xb-xa;
  dy=yb-ya;
  if(abs(dx)>abs(dy)) steps=abs(dx);
  else steps=abs(dy);
  delta_x=(float)dx/(float)steps;
  delta_y=(float)dy/(float)steps;
  x=xa;
  y=ya;
  putpixel(x,y,c);
  for(k=1;k<=steps;k++)
  {
   x+=delta_x;
   y+=delta_y;
   putpixel(x,y,c);
  }
}

main()
{
  int i;
  clock_t t1,t2;
  int driver=DETECT,mode=0;
  initgraph(&driver,&mode,"");
  cleardevice();

  t1=clock();  /*取當前時間*/
  for(i=0;i<200;i++)
    dda_line(10,10,400,390, WHITE);
  t2=clock();  /*取當前時間*/
  printf(" dda_line() use time: %fn",(double)(t2-t1));

  t1=clock();  /*取當前時間*/
  for(i=0;i<200;i++)
    line(10,10,400,390);  /*line()爲Tc2.0系統提供的畫直線函數*/
  t2=clock();  /*取當前時間*/
  printf(" line() use time: %fn",(double)(t2-t1));

 getch();
 closegraph();

}