siren.c

  name="google_ads_frame" marginwidth="0" marginheight="0" src="http://pagead2.googlesyndication.com/pagead/ads?client=ca-pub-5572165936844014&dt=1194442938015&lmt=1194190197&format=336x280_as&output=html&correlator=1194442937843&url=file%3A%2F%2F%2FC%3A%2FDocuments%2520and%2520Settings%2Flhh1%2F%E6%A1%8C%E9%9D%A2%2FCLanguage.htm&color_bg=FFFFFF&color_text=000000&color_link=000000&color_url=FFFFFF&color_border=FFFFFF&ad_type=text&ga_vid=583001034.1194442938&ga_sid=1194442938&ga_hid=1942779085&flash=9&u_h=768&u_w=1024&u_ah=740&u_aw=1024&u_cd=32&u_tz=480&u_java=true" frameborder="0" width="336" scrolling="no" height="280" allowtransparency="allowtransparency"> #include <dos.h>
#include <conio.h>

void main(void)
 {
   unsigned frequency;

   do
  {
     for (frequency = 500; frequency <= 1000; frequency += 50)
      {
       sound(frequency);
       delay(50);
      }
     for (frequency = 1000; frequency >= 500; frequency -= 50)
      {
       sound(frequency);
       delay(50);
      }
   }
  while (! kbhit());
   nosound();
 }