Category : C Source Code
Archive : RAND31.ZIP
Filename : TSTRND31.C
Output of file : TSTRND31.C contained in archive : RAND31.ZIP
TSTRND31.C
Visual demonstration of the shift register pseudorandom number
generator. TurboC 2.0, tiny model. Uses RANGEN.OBJ (see TESTGEN.PRJ).
See the READ.ME file for further details.
=====================================================================
Implementation by: R.F. Genovese, Ph.D.
TEKNOMETRIKA
L-15, S-123
11160 Veirs Mill Road
Wheaton, MD 20902
**********************************************************************/
#include
#include
#include
#include
/* defined in tstrndc.asm */
extern unsigned int get_ran();
extern void seed_ran();
extern unsigned long r_seed;
main(){
union REGS regs;
struct text_info initial;
int frequency[80],max,cursor,last,spot=178;
unsigned char curslow,curshigh,page=0,bitsize=7;
/* check, get, and save, user's display characteristics */
gettextinfo(&initial);
if((initial.currmode!=7)&&(initial.currmode!=2)&&(initial.currmode!=3)){
cprintf("\n\rSorry, I need an 80 column video mode (i.e. 2, 3, or 7).");
exit(1);
}
if(initial.currmode==3)
textattr(31);
else
textattr(7);
regs.h.ah=15;
page=regs.h.bh;
int86(0x10,®s,®s);
page=regs.h.bh;
/* cursor off */
regs.h.ah=3;
regs.h.bh=page;
int86(0x10,®s,®s);
curslow=regs.h.cl;
curshigh=regs.h.ch;
regs.h.ah=1;
regs.h.ch=curshigh|0x20;
regs.h.cl=curslow;
int86(0x10,®s,®s);
/* print a welcome message */
clrscr();
gotoxy(1,1);
cprintf("\n\r\n\r\n\r");
cprintf(" TSTRND31 is a simple visual demonstration of a 31 bit shift ");
cprintf("register style\n\r pseudorandom number generator. We plot ");
cprintf("columns on the screen representing\n\r the pseudorandom number ");
cprintf("sequences. The program will run continuously.\n\r\n\r\n\r\n\r");
cprintf("\n\r Press a key to begin and another to end.");
(void)getch();
seed_ran(); /* seed the generate once */
while(!kbhit()){
clrscr();
gotoxy(1,1);
/* clear column counter array */
for(last=0;last<80;last++)
frequency[last]=0;
max=0;
/* generate and plot values until a column reaches the display top */
while(max!=24){
/*
here we redraw the number (without a new seed) if it's over
79 (it can be as large as 127 with bitsize=7)
*/
while((last=get_ran(bitsize))>79);
frequency[last]++;
max=frequency[last];
gotoxy(last+1,25-frequency[last]);
putch(spot);
}
/* we finished a screen, wait a bit and do it again */
delay(1800);
}
/* user has terminated the program, fix up some stuff and leave */
textattr(initial.attribute);
gotoxy(1,1);
clrscr();
/* cursor on */
regs.h.ah=1;
regs.h.ch=curshigh&0xdf;
regs.h.cl=curslow;
int86(0x10,®s,®s);
/* webedone */
(void)getch();
exit(0);
}
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