omg C++

[dj_de]

Usage: runtime program [arguments]
runtime returns the total turnaround time of program in number of milliseconds.

Example

$ runtime who >/dev/null
Total elasped time: 70 milliseconds

$ runtime sleep 3
Total elasped time: 3030 milliseconds


Implementation Details

   * Spawn a new process using fork.
   * Invoke program in the child process using a version of exec.
   * Wait for the child to finish using wait.
   * On Unix or Linux, time the program use the gettimeofday function to compute the elapsed time.
   * Write the time output to stderr. 

fork, exec, and wait, are system calls. They are documented in Section 2 of the online Programmer's Manual. On Unix, use the command man -s 2 function to access the documentation.

 

HOW TO DO

[Hamburglar]

Beats the hell outta me..

 

MikeJ???

[MikeJ]

/* dj.c a program that dont do jack shit */

#include <stdio.h>

#include <sys/types.h> /* this shit is for */
#include <unistd.h>    /* ())=======D */
#include <sys/time.h> /* lol */
#include <sys/wait.h> /*   the system calls */

int main(int argc, char **argv)
{
 struct timeval tv;         /* For getting time, from sys/time.h */
 struct timezone tz;

 int pid; /* process id */
 long int t; /* for holding seconds */

 char *newargv[20];
 char *file[20];
 int i, j, a;

 if ( argc > 1 )
 {
   file[0] = argv[1];
   a = 0;
   while ( --argc > 0 )
     newargv[a++] = (*++argv); /* build arguments */
   
   newargv[a] = NULL;
     
   j = 0;

   gettimeofday(&tv, &tz);
   printf("%s", asctime(localtime(&tv.tv_sec)));
   t = (long int) time(0);
   printf("time since 00:00:00 GMT Jan/1/1970 is %d secs\n", t);

   while ( j < 1 ) {
     j++;
     if ( ( pid = fork() ) == 0 ) {
       i = execvp( file[0], newargv );
     } else {
       wait( &i );
     }
   }

   gettimeofday(&tv, &tz);
   printf("%s", asctime(localtime(&tv.tv_sec)));
   printf("Elapsed time is %ld secs\n", (long int) time(0) - t);    
 }
 return 0;
}

 

this sorta works but i was too lazy to perfect it, uh hopefully it helps, btw here is sample output:

 

[mikej@snapzilla mikej]$ ./dj sleep 4

Sun Oct 17 15:03:33 2004

time since 00:00:00 GMT Jan/1/1970 is 1098050613 secs

Sun Oct 17 15:03:37 2004

Elapsed time is 4 secs

[mikej@snapzilla mikej]$

[dj_de]

THANKS

 

i have 2 questions though:

 

1. did u use some peticular command to compile it?

2. if i get rid of some of those printf statements about timeofday, will it affect anything?

[MikeJ]

THANKS

 

i have 2 questions though:

 

1. did u use some peticular command to compile it?

2. if i get rid of some of those printf statements about timeofday, will it affect anything?

 

1. just gcc (gcc -o file file.c)

 

2. it shouldn't

[MikeJ]

ps that second while loop with the incrementing J is pretty useless

[dj_de]

// LOL NAME
// gcc

#include <stdio.h>
#include <sys/types.h> 
#include <unistd.h>    
#include <sys/time.h>
#include <sys/wait.h>

int main(int argc, char **argv)
{
struct timeval tv;
struct timezone tz;

int pid;
long double t;

char *newargv[20];
char *file[20];
int i, a;

if ( argc > 1 )
{
  file[0] = argv[1];
  a = 0;
  while ( --argc > 0 )
    newargv[a++] = (*++argv);
  
  newargv[a] = NULL;

  gettimeofday(&tv, &tz);
  t = (long double) time(0);

    if ( ( pid = fork() ) == 0 ) {
      i = execvp( file[0], newargv );
    } else {
      wait( &i );
    }
  }

  gettimeofday(&tv, &tz);
  printf("Elapsed time is %ld ms\n", (long double) (time(0) - t)*10);    
}
return 0;
}

[MikeJ]

// LOL NAME
// gcc

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/wait.h>

int main(int argc, char **argv)
{
 struct timeval tv;
 struct timezone tz;

 int pid;
 double t;

 char *newargv[20];
 char *file[20];
 int i, a;

 if ( argc > 1 )
 {
   file[0] = argv[1];
   a = 0;
   while ( --argc > 0 )
     newargv[a++] = (*++argv);

   newargv[a] = NULL;

   gettimeofday(&tv, &tz);
   t = time(0);

   if ( ( pid = fork() ) == 0 ) {
     i = execvp( file[0], newargv );
   } else {
     wait( &i );
   }

   gettimeofday(&tv, &tz);
   printf("Elapsed time is %f ms\n", (double) (time(0) - t) * 1000);
 }
 return 0;
}

[MikeJ]

ps: it's only getting rounded seconds, uhhhhh hopefully your teacher wont notice (it will still say 3000ms, but never like 3029 ms)

 

lunix :darkstar:

[Kungfubar]

ps: it's only getting rounded seconds, uhhhhh hopefully your teacher wont notice (it will still say 3000ms, but never like 3029 ms) 

 

lunix :darkstar:

<{POST_SNAPBACK}>

 

MikeJ is my hero :eek: