#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "ps.h"

void frame(void);
void drawline(void);

int main()
{   
     init();
     viewport(0.2, 0.2, 0.8, 0.8); 
     xyworld(-1.2, -1.2, 1.2, 1.2); 
     frame();
     drawline();
     fin();

     return 0;
}

void frame()
{
     int n,i;double x,y,dx,dy;
     arrow( -1.1, 0.0, 1.1, 0.0, 0.02, 0.0, 1.0);
     arrow( 0.0, -1.1, 0.0, 1.1, 0.02, 0.0, 1.0);
     text(1.0,-0.1,1,"x");
     text(-0.1,1.0,1,"y");
     text(-0.1,-0.1,1,"O");
     n=10;
       for (i=1;i<=n;i++){ 
        x=0.1*i; if(i/5*5==i) dy=0.02; else  dy=0.01; 
        line( -x, -dy, -x, dy, 0.0, 1.0, 1); 
        line( x, -dy, x, dy, 0.0, 1.0, 1);
        }
     for(i=1;i<=n;i++){
        y=0.1*i; if(i/5*5==i) dx=0.02; else  dx=0.01;
        line( -dx, -y, dx, -y, 0.0, 1.0, 1);
        line( -dx, y, dx, y, 0.0, 1.0, 1);
        } stroke();
     return;
}

void drawline(void)
{
     int i,nx=100;double x,y,t;
 
      x=-1.0;  y=0.0;
      linewidth(1.5);
      plot( x, y, 3);
        for (i=-nx+1;i<=nx;i++){
          t = (double)i/(double)nx;x = t; y = sin(t*3.14159);
        plot( x, y, 2);
         } stroke();
    return;
}