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

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

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

void frame()
{
     int n,i;double x,y,dx,dy; int m;char* str1;
     setgray(0.2);
     arrow( -1.1, 0.0, 1.1, 0.0, 0.02);
     arrow( 0.0, -1.1, 0.0, 1.1, 0.02);
     textx(1.15, 0.03,"x");
     texty( 0.02,1.15,"y");
     textx(-0.13,-0.0,"O");
     textx( 0.5, -0.0,"pi/2");
     textx( 1.0, -0.0,"pi");
     textx(-0.5, -0.0,"-pi/2");
     textx(-1.0, -0.0,"-pi");
     texty( 0.02,  1.0,"1");
     texty( 0.02,  0.5,"0.5");
     texty( 0.02, -0.5,"-0.5");
     texty( 0.02, -1.0,"-1");
     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); 
        line( x, -dy, x, dy);
        }
     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);
        line( -dx, y, dx, y);
        } stroke();
     return;
}

void drawline(void)
{
     int i,nx=100;double x,y,t;
 
      x=-1.0;  y=0.0;
      linewidth(1.5);
      setgray(0.0);
      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;
}