Q(uick)BASIC Function: TIMER

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TIMER

A function that returns the number of seconds elapsed since midnight

Worth knowing

Useful and cross-version information about the programming environments of QBasic and QuickBasic.

Syntax

TIMER

Description/Parameter(s)

Use TIMER to time programs or parts of programs, or with the RANDOMIZE statement to seed the random-number generator.

Example

RANDOMIZE TIMER

Syntax

TIMER

Description/Parameter(s)

The TIMER function can be used with the RANDOMIZE statement to generate a random number. It can also be used to time programs or parts of programs.

Example

The following program searches for the prime numbers from 3 to 10,000 using a variation of the Sieve of Eratosthenes. The TIMER function is used to time the program.

'*** Programming example for the TIMER function
'
DEFINT A-Z
CONST UNMARK = 0, MARKIT = NOT UNMARK
DIM Mark(10000)
CLS                     'Clear the screen
Start! = TIMER
Num = 0
FOR N = 3 TO 10000 STEP 2
   IF NOT Mark(N) THEN
      'PRINT N,   'To print the primes, remove the
                  'remark delimiter in front of the
                  'PRINT statement.
      Delta = 2*N
      FOR I = 3*N TO 10000 STEP Delta
         Mark(I) = MARKIT
      NEXT
      Num = Num + 1
   END IF
NEXT
Finish! = TIMER
PRINT
PRINT "Program took";Finish! - Start!;
PRINT "seconds to find the";Num;"primes"
END

Sample Output:

Program took .1601563 seconds to find the 1228 primes

Syntax

TIMER

Description/Parameter(s)

Usage Notes

The TIMER function can be used with the RANDOMIZE statement to generate a random number. It also can be used to time programs or parts of programs.

Example

The following program searches for the prime numbers from 3 to 10,000 using a variation of the Sieve of Eratosthenes. The TIMER function is used to time the program.

DEFINT A-Z
CONST UNMARK = 0, MARKIT = NOT UNMARK
DIM Mark(10000)
CLS                     'Clear the screen.
Start! = TIMER
Num = 0
FOR N = 3 TO 10000 STEP 2
   IF NOT Mark(N) THEN
      'PRINT N,   'To print the primes, remove the
                  'remark delimiter in front of the
                  'PRINT statement.
      Delta = 2 * N
      FOR I = 3 * N TO 10000 STEP Delta
         Mark(I) = MARKIT
      NEXT
      Num = Num + 1
   END IF
NEXT
Finish! = TIMER
PRINT
PRINT "Program took"; Finish! - Start!;
PRINT "seconds to find the"; Num; "primes"
END

Sample Output:

Program took .28125 seconds to find the 1228 primes