水电出版社的《C语言程序设计实训》源代码

				 /* 9-1.c可生成噪声的主程序 */
				 #define FALSE 0
				 #define TRUE 1
				 #include
				main()
				{
				int snd;    /*  which sound to produce  */
				int cnt;    /* number of times to repeat sound */
				int note;   /* Current note, when sweeping frequencies  */
				while (TRUE) {
				/* Male Sure any previous sounds ave turned off.  */
				   nosound();
				/* Ask the user for which type of sounf*/
				printf ("1-siren;2-overload;3-whoop;4-phaser; 0-exit");
				/* read the answer */
				   scanf ("%d",&snd);
				/* if the  answer it to exit ,do so. */
				   if (snd==0)
				   break;
				/* Ask how many times to repast the sound. */
				printf ("Nunger of times:");
				/* get the answer */
				scanf("%d",&cnt);
				/* repeat the sound the number of time specifed */
				while(cnt--){
				/* swich on type of sound to produce*/
				switch (snd)
				{case 1:
				  /* do a siren:sweep up */
				for (note=1000;note>150;note-=10)
				{
				sound(note);
				delay(20);
				}
				/* Sweep down */
				for (;note				{
				sound(note);
				  delay(20);
				}
				break;
				case 2:  /* do an overload. sweep up */
						for (note=4000;note>10;note-=10)
				{
				sound(note);
				delay(70);
				}
				break;
				case 3:
					   /* do a whoop: Sweep up*/
					   for (note=1000;note>10;note-=10)
						 {
						 sound (note);
				delay (200);
				}
				break;
				case 4:
					  /* do a phaser: sweep down */
					  for (note=60; note				{
				sound (note);
				delay(100);
				}
				break;
				default:
						   /* unknown,ask a gain */
						   printf ( "Invalid entry;try again \n");
						   break;
				}
				}
				}
				}