Category : C Source Code
Archive   : C-DATES.ZIP
Filename : DAYS.C

/************************************************************************/
/* (c) 1987 by James N. Seed, Dallas, TX - all rights reserved. */
/* */
/* This program is provided for example purposes only. It, and/or */
/* its executable equivalent, may not be sold or distributed in any */
/* form for profit, without the prior written consent of the author. */
/************************************************************************/

#define LINT_ARGS /* wholly advisable!!! */

#pragma check_stack- /* special for MSC */

#include
#include
#include
#include

static char *errtyp1 = "\nerror: cannot interpret the %s in the %s date.\n";
static char *errtyp2 = "\nerror: %s date is not a valid date.\n";

static char *fldnme[3] = { "month", "day", "year" }; /* this is for the */
static char *dtenme[2] = { "first", "second" }; /* error output. */

_setenvp() { } /* special for MSC */

main( argc, argv )

int argc;
char **argv;

{
unsigned int gregdte[3], i; /* m, d, & y ( & index ) */
unsigned long julian[2]; /* holds 2 julian dates */
char dtestr[29]; /* to hold verbose dates */
char *nxtfld; /* for dividing parms */
unsigned int chkdte[3]; /* used to check date */

if ( argc-- != 3 ) /* two parms input ? */
{
printf( "\n DAYS is a program that calculates the number of days that" );
printf( "\n ==== exist between any two dates.\n" );
printf( "\nusage: DAYS date1 date2" );
printf( "\n\nwhere:" );
printf( "\n\tdate1 is the starting date of the period, and" );
printf( "\n\tdate2 is the ending date of the period." );
printf( "\n\n- Both dates MUST be input in the \"month/day/year\" format.\n" );

return( 0 );
}

/*******************************************************************/
/* The following loop converts the two input dates to julian longs */
/*******************************************************************/

while ( argc ) /* for both dates, */
{
for ( i = 0; i < 2; ++i ) /* pick off m & d */
{
if ( gregdte[i] = atoi( argv[argc] ) )
{
if ( nxtfld = strstr( argv[argc], "/" ) )
{
argv[argc] = ++nxtfld;
}
else
{
printf( errtyp1, fldnme[++i], dtenme[--argc] );
return( 1 );
}
}
else
{
printf( errtyp1, fldnme[i], dtenme[--argc] );
return( 1 );
}
}

gregdte[i] = atoi( argv[argc] ); /* then pick off y */

/*********************************************************/
/* this line converts the m, d, & y to a JULIAN date */
/*********************************************************/

julian[--argc] = gtoj( gregdte[0], gregdte[1], gregdte[2] );

/*****************************************************/
/* these lines check to see if the date is valid */
/*****************************************************/

jtog( julian[argc], (char *)chkdte, 0 );

for ( i = 0; i < 3; ++i )
{
if ( chkdte[i] != gregdte[i] )
{
printf( errtyp2, dtenme[argc] );
return( 1 );
}
}
}

/*******************************************************************/
/* this line computes the NUMBER OF DAYS between the two dates */
/*******************************************************************/

printf( "\nThere are %li days between the two dates,",
daycnt( julian[0], julian[1], 0 ) );

/******************************************************/
/* these lines create the VERBOSE GREGORIAN dates */
/******************************************************/

fulldte( julian[0], dtestr );

printf( "\n\n\t %s", dtestr );

fulldte( julian[1], dtestr );

printf( " and %s.", dtestr );

/*******************************************************************/
/* this line computes the weekday, Saturday, and Sunday counts */
/*******************************************************************/

printf( "\n\nOf these, %li are weekdays, %li are Saturdays, and %li are Sundays.\n",
daycnt( julian[0], julian[1], 2 ),
satcnt( julian[0], julian[1] ),
suncnt( julian[0], julian[1] ) );

return( 0 );
}