QB Versus C, Benchmark Time Comparison for Recursive Program (43782)

SUMMARY

The Towers of Hanoi is a problem that can be programmatically solved through the use of recursion. Listed below are the recursive implementations in QuickBasic version 4.50 and Microsoft C version 5.10. When compiled with the compiler option giving the greatest speed (BC /O stand-alone option), the QuickBasic .EXE routine was roughly 40 percent slower than the C routine. No coprocessor was used because the program uses all integers and no floating-point calculations.

This benchmark comparison for QuickBasic 4.50 is similar for Microsoft QuickBasic versions 4.00 and 4.00b, for Microsoft Basic Compiler versions 6.00 and 6.00b for MS-DOS and MS OS/2, and for Microsoft Basic PDS versions 7.00 and 7.10 for MS-DOS and MS OS/2.

MORE INFORMATION

The table below shows the execution speeds (in seconds) of the recursive routine in both QuickBasic version 4.50 and Microsoft C version 5.10. The benchmark was performed on a Wyse 286, running MS-DOS 3.30, operating at 10 megahertz. As you can see in the following timings (based on the number of disks on the Hanoi Towers), the QuickBasic routine was roughly 40 percent slower than the C routine:

   Number of Disks       QuickBasic 4.50      C 5.10
   ---------------       ---------------      ------

          1                  0.0000           0.0000
          2                  0.0000           0.0000
          3                  0.0000           0.0000
          4                  0.0000           0.0000
          5                  0.0000           0.0000
          6                  0.0000           0.0000
          7                  0.0000           0.0000
          8                  0.0125           0.0000
          9                  0.0368           0.0000
         10                  0.0624           0.0000
         11                  0.1093           0.0000
         12                  0.1601           0.0802
         13                  0.3789           0.1739
         14                  0.8203           0.3674
         15                  1.5898           0.7812
         16                  3.1911           1.7310
         17                  6.4296           3.8761
         18                  12.796           7.2687
         19                  25.539           15.234
         20                  51.132           31.021

Code Example

REM ** QuickBasic program:
REM Compile as follows:  BC HANOI.BAS/O;
REM Link as follows:     LINK HANOI.OBJ;
DEFINT A-Z
DECLARE SUB HANOI(DISKS,TOWERA(),TOWERB(),TOWERC())
CLEAR ,, 4096
DIM TOWERA(2)
DIM TOWERB(2)
DIM TOWERC(2)
PRINT
PRINT"                   RECURSIVE TOWERS OF HANOI"
DO
INPUT "NUMBER OF DISKS? ", DISKS
PRINT
     IF DISKS<>0 THEN
          TOWERA(0)=1
          TOWERB(0)=2
          TOWERC(0)=3
          PRINT
          CALL HANOI(DISKS,TOWERA(),TOWERB(),TOWERC())
     END IF
LOOP UNTIL DISKS=0
END

FUNCTION WHICHTOWER$(TOWER%)
  SELECT CASE TOWER%
     CASE 1:     WHICHTOWER$=" A "
     CASE 2:     WHICHTOWER$=" B "
     CASE 3:     WHICHTOWER$=" C "
  END SELECT
END FUNCTION

SUB HANOI (DISKS,TOWERA(),TOWERB(),TOWERC())
     IF DISKS=1 THEN
          DESTINATION$=WHICHTOWER$(BYVAL TOWERC(0))
          SOURCE$=WHICHTOWER$(BYVAL TOWERA(0))
          PRINT "MOVED DISK FROM"; SOURCE$;"TO";DESTINATION$
     ELSE
           CALL HANOI(DISKS-1,TOWERA(),TOWERC(),TOWERB())
          DESTINATION$=WHICHTOWER$(BYVAL TOWERC(0))
          SOURCE$=WHICHTOWER$(BYVAL TOWERA(0))
          PRINT "MOVED DISK FROM"; SOURCE$;"TO";DESTINATION$
          CALL HANOI(DISKS-1,TOWERB(),TOWERA(),TOWERC())
     END IF
END SUB


/*  C program:  */ 
#include <time.h>
#include <stdio.h>
char *source=" Z  ",*destination=" Z  ";

void hanoi(disks,TowerA,TowerB,TowerC)
int disks;
int TowerA,TowerB,TowerC;
{
    extern char *source,*destination;

    if (disks == 1)
     {
       switch (TowerA)
        {
         case 1 :
             source=" A \0";
             break;
      case 2 :
             source=" B \0";
             break;
      case 3 :
             source=" C \0";
             break;
        }
       switch (TowerC)
     {
      case 1 :
             destination=" A \0";
             break;
      case 2 :
             destination=" B \0";
             break;
      case 3 :
             destination=" C \0";
             break;
        }
      /*printf("\nMOVED DISK FROM %s to %s",source,destination);*/ 
     }
   else
     {
      hanoi(disks-1,TowerA,TowerC,TowerB);
       switch (TowerA)
        {
         case 1 :
             source=" A \0";
             break;
      case 2 :
             source=" B \0";
             break;
      case 3 :
             source=" C \0";
             break;
        }
       switch (TowerC)
     {
      case 1 :
             destination=" A \0";
             break;
      case 2 :
             destination=" B \0";
             break;
      case 3 :
             destination=" C \0";
             break;
        }
       /*printf("\nMOVED DISK FROM %s to %s",source,destination);*/ 
    hanoi(disks-1,TowerB,TowerA,TowerC);
    }
}

main ()
{
   int           TowerA=1,TowerB=2,TowerC=3,disks,thatone;
   long       start=01,finish=01;
   clock_t     clock(void);
   float       amnttime;

   printf("number of disks? ");
   scanf("%d",&disks);
   while (disks!=0)
   {
     start=(long)clock();
     hanoi(disks,TowerA,TowerB,TowerC);
     finish=(long)clock();
     amnttime=(float)((finish-start)/(float)CLK_TCK);
     printf("\nPROGRAM TOOK %04.04f", amnttime);
     printf(" SECONDS WITH %d DISKS",disks);
     printf("\nnumber of disks? ");
     scanf("%d",&disks);
   }
  fcloseall();

}