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Finds the difference between two times.

double difftime( 
   time_t timer1,
   time_t timer0 


Ending time.
Beginning time.

Return Value

difftime returns the elapsed time in seconds, from timer0 to timer1. The value returned is a double-precision, floating-point number.


The difftime function computes the difference between the two supplied time values timer0 and timer1.


Routine Required header Compatibility
difftime <time.h> ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP

For additional compatibility information, see Compatibility in the Introduction.


All versions of the C run-time libraries.


// crt_difftime.c
/* This program calculates the amount of time
 * needed to do a floating-point multiply 500 million times.

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main( void )
   time_t   start, finish;
   long loop;
   double   result, elapsed_time;

   printf( "Multiplying 2 floating point numbers 500 million times...\n" );
   time( &start );
   for( loop = 0; loop < 500000000; loop++ )
      result = 3.63 * 5.27; 
   time( &finish );

   elapsed_time = difftime( finish, start );
   printf( "\nProgram takes %6.0f seconds.\n", elapsed_time );

Sample Output

Multiplying 2 floating point numbers 500 million times...

Program takes      5 seconds.

See Also

Floating-Point Support Routines | Time Management Routines | time | Run-Time Routines and .NET Framework Equivalents