random value at random time

my motive is to get random variable at every start of program.so it does not show same sequence when it run again and again

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int main()

{
    srand( time ( NULL ) );
    cout<<rand();
}



when i run this program in code::block the following program is opening with error in new tab called TIME.H
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/*
 * time.h
 * This file has no copyright assigned and is placed in the Public Domain.
 * This file is a part of the mingw-runtime package.
 * No warranty is given; refer to the file DISCLAIMER within the package.
 *
 * Date and time functions and types.
 *
 */

#ifndef	_TIME_H_
#define	_TIME_H_

/* All the headers include this file. */
#include <_mingw.h>

#define __need_wchar_t
#define __need_size_t
#define __need_NULL
#ifndef RC_INVOKED
#include <stddef.h>
#endif	/* Not RC_INVOKED */

/*
 * Number of clock ticks per second. A clock tick is the unit by which
 * processor time is measured and is returned by 'clock'.
 */
#define	CLOCKS_PER_SEC	((clock_t)1000)
#define	CLK_TCK		CLOCKS_PER_SEC


#ifndef RC_INVOKED

/*
 * A type for storing the current time and date. This is the number of
 * seconds since midnight Jan 1, 1970.
 * NOTE: This is also defined in non-ISO sys/types.h.
 */
#ifndef _TIME_T_DEFINED
typedef	long	time_t;
#define _TIME_T_DEFINED
#endif

#ifndef __STRICT_ANSI__
/* A 64-bit time_t to get to Y3K */
#ifndef _TIME64_T_DEFINED
typedef __int64 __time64_t;
#define _TIME64_T_DEFINED
#endif
#endif
/*
 * A type for measuring processor time (in clock ticks).
 */
#ifndef _CLOCK_T_DEFINED
typedef	long	clock_t;
#define _CLOCK_T_DEFINED
#endif

#ifndef _TM_DEFINED
/*
 * A structure for storing all kinds of useful information about the
 * current (or another) time.
 */
struct tm
{
	int	tm_sec;		/* Seconds: 0-59 (K&R says 0-61?) */
	int	tm_min;		/* Minutes: 0-59 */
	int	tm_hour;	/* Hours since midnight: 0-23 */
	int	tm_mday;	/* Day of the month: 1-31 */
	int	tm_mon;		/* Months *since* january: 0-11 */
	int	tm_year;	/* Years since 1900 */
	int	tm_wday;	/* Days since Sunday (0-6) */
	int	tm_yday;	/* Days since Jan. 1: 0-365 */
	int	tm_isdst;	/* +1 Daylight Savings Time, 0 No DST,
				 * -1 don't know */
};
#define _TM_DEFINED
#endif

#ifdef	__cplusplus
extern "C" {
#endif

_CRTIMP clock_t __cdecl __MINGW_NOTHROW	clock (void);
g_CRTIMP time_t __cdecl __MINGW_NOTHROW	time (time_t*);
_CRTIMP double __cdecl __MINGW_NOTHROW	difftime (time_t, time_t);
_CRTIMP time_t __cdecl __MINGW_NOTHROW	mktime (struct tm*);

/*
 * These functions write to and return pointers to static buffers that may
 * be overwritten by other function calls. Yikes!
 *
 * NOTE: localtime, and perhaps the others of the four functions grouped
 * below may return NULL if their argument is not 'acceptable'. Also note
 * that calling asctime with a NULL pointer will produce an Invalid Page
 * Fault and crap out your program. Guess how I know. Hint: stat called on
 * a directory gives 'invalid' times in st_atime etc...
 */
_CRTIMP char* __cdecl __MINGW_NOTHROW		asctime (const struct tm*);
_CRTIMP char* __cdecl __MINGW_NOTHROW		ctime (const time_t*);
_CRTIMP struct tm*  __cdecl __MINGW_NOTHROW	gmtime (const time_t*);
_CRTIMP struct tm*  __cdecl __MINGW_NOTHROW	localtime (const time_t*);

_CRTIMP size_t __cdecl __MINGW_NOTHROW		strftime (char*, size_t, const char*, const struct tm*);

#ifndef __STRICT_ANSI__

extern _CRTIMP void __cdecl __MINGW_NOTHROW	_tzset (void);

#ifndef _NO_OLDNAMES
extern _CRTIMP void __cdecl __MINGW_NOTHROW	tzset (void);
#endif

_CRTIMP char* __cdecl __MINGW_NOTHROW	_strdate(char*);
_CRTIMP char* __cdecl __MINGW_NOTHROW	_strtime(char*);

/* These require newer versions of msvcrt.dll (6.10 or higher). */
#if __MSVCRT_VERSION__ >= 0x0601
_CRTIMP __time64_t __cdecl __MINGW_NOTHROW  _time64( __time64_t*);
_CRTIMP __time64_t __cdecl __MINGW_NOTHROW  _mktime64 (struct tm*);
_CRTIMP char* __cdecl __MINGW_NOTHROW _ctime64 (const __time64_t*);
_CRTIMP struct tm*  __cdecl __MINGW_NOTHROW _gmtime64 (const __time64_t*);
_CRTIMP struct tm*  __cdecl __MINGW_NOTHROW _localtime64 (const __time64_t*);
#endif /* __MSVCRT_VERSION__ >= 0x0601 */

/*
 * _daylight: non zero if daylight savings time is used.
 * _timezone: difference in seconds between GMT and local time.
 * _tzname: standard/daylight savings time zone names (an array with two
 *          elements).
 */
#ifdef __MSVCRT__

/* These are for compatibility with pre-VC 5.0 suppied MSVCRT. */
extern _CRTIMP int* __cdecl __MINGW_NOTHROW	__p__daylight (void);
extern _CRTIMP long* __cdecl __MINGW_NOTHROW	__p__timezone (void);
extern _CRTIMP char** __cdecl __MINGW_NOTHROW	__p__tzname (void);

__MINGW_IMPORT int	_daylight;
__MINGW_IMPORT long	_timezone;
__MINGW_IMPORT char 	*_tzname[2];

#else /* not __MSVCRT (ie. crtdll) */

#ifndef __DECLSPEC_SUPPORTED

extern int*	_imp___daylight_dll;
extern long*	_imp___timezone_dll;
extern char**	_imp___tzname;

#define _daylight	(*_imp___daylight_dll)
#define _timezone	(*_imp___timezone_dll)
#define _tzname		(*_imp___tzname)

#else /* __DECLSPEC_SUPPORTED */

__MINGW_IMPORT int	_daylight_dll;
__MINGW_IMPORT long	_timezone_dll;
__MINGW_IMPORT char*	_tzname[2];

#define _daylight	_daylight_dll
#define _timezone	_timezone_dll

#endif /* __DECLSPEC_SUPPORTED */

#endif /* not __MSVCRT__ */

#ifndef _NO_OLDNAMES

#ifdef __MSVCRT__

/* These go in the oldnames import library for MSVCRT. */
__MINGW_IMPORT int	daylight;
__MINGW_IMPORT long	timezone;
__MINGW_IMPORT char 	*tzname[2];

#else /* not __MSVCRT__ */

/* CRTDLL is royally messed up when it comes to these macros.
   TODO: import and alias these via oldnames import library instead
   of macros.  */

#define daylight        _daylight
/* NOTE: timezone not defined as macro because it would conflict with
   struct timezone in sys/time.h.
   Also, tzname used to a be macro, but now it's in moldname. */
__MINGW_IMPORT char 	*tzname[2];

#endif /* not __MSVCRT__ */

#endif	/* Not _NO_OLDNAMES */
#endif	/* Not __STRICT_ANSI__ */

#ifndef _WTIME_DEFINED
/* wide function prototypes, also declared in wchar.h */
#ifndef __STRICT_ANSI__
#ifdef __MSVCRT__
_CRTIMP wchar_t* __cdecl __MINGW_NOTHROW	_wasctime(const struct tm*);
_CRTIMP wchar_t* __cdecl __MINGW_NOTHROW	_wctime(const time_t*);
_CRTIMP wchar_t* __cdecl __MINGW_NOTHROW	_wstrdate(wchar_t*);
_CRTIMP wchar_t* __cdecl __MINGW_NOTHROW	_wstrtime(wchar_t*);
#if __MSVCRT_VERSION__ >= 0x0601
_CRTIMP wchar_t* __cdecl __MINGW_NOTHROW	_wctime64 (const __time64_t*);
#endif
#endif /*  __MSVCRT__ */
#endif /* __STRICT_ANSI__ */
_CRTIMP size_t __cdecl __MINGW_NOTHROW		wcsftime (wchar_t*, size_t, const wchar_t*, const struct tm*);
#define _WTIME_DEFINED
#endif /* _WTIME_DEFINED */

#ifdef	__cplusplus
}
#endif

#endif	/* Not RC_INVOKED */

#endif	/* Not _TIME_H_ */

 


help me please.is there any alternative solution or something else
For the record posting the contents of time.h wont help us see your error. It should of told you more than that.

Try including cstdlib and ctime which are the C++ versions for srand/time.
closed account (j3Rz8vqX)
That tab is the time_header file, unless you know exactly which line it is that crashing, the header file isn't necessary - as we all have that header file available.

Your actual code:
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int main()
{
    srand( time ( NULL ) );
    cout<<rand();
}

Should work unless
What does the error say?

http://www.cplusplus.com/reference/ctime/time/
http://www.cplusplus.com/reference/cstdlib/srand/
http://www.cplusplus.com/reference/cstdlib/rand/

Are you using the following code?
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#include <cstdlib>
#include <ctime> 


Try the below code:
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#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;
int main()
{
    srand( time ( NULL ) );
    cout<<rand();
}

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#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;
int main()
{
    srand( time ( NULL ) );
    cout<<rand();
}

this is the exact code i am running

this is the screen i am getting after building program when i havve cstdlib.h and cstime.h

http://postimg.org/image/nqus4kdod/

this is the screen i am getting after building program when i havve stdlib.h and time.h

http://postimg.org/image/5hlv1r2n9/


help me get out of this please
Last edited on
Have you modified your time.h file at all?

This looks suspicious:
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_CRTIMP clock_t __cdecl __MINGW_NOTHROW	clock (void);
g_CRTIMP time_t __cdecl __MINGW_NOTHROW	time (time_t*);
_CRTIMP double __cdecl __MINGW_NOTHROW	difftime (time_t, time_t);
_CRTIMP time_t __cdecl __MINGW_NOTHROW	mktime (struct tm*);

Try removing the "g" on line 85 and see what happens.
closed account (j3Rz8vqX)
Heh, I don't believe there is suppose to be a g in front of that command in the time.h

g_CRTIMP time_t __cdecl __MINGW_NOTHROW time (time_t*);
Good call to show the lib, but next time, maybe just the one line that failed would be good enough.

http://sourceforge.net/p/mingw/mingw-org-wsl/ci/3e0359b62de2b083a9b208f8db61745080a21654/tree/include/time.h?barediff=a7179dcfc8d0c44b1717e272da56ee1399a6f95c

ctrl+f: _CRTIMP time_t __cdecl __MINGW_NOTHROW time (time_t*);

Possibly remove the g?

It's suppose to be:
_CRTIMP time_t __cdecl __MINGW_NOTHROW time (time_t*);

Edit: Aw, you beat me to the punch >.<
Last edited on
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