Thread: C Ranges

When you put back in the missing "=" after static const DATE_RANGE date_range[] it will compile, but it doesn't actually work, as all values of "julian" (bar zero) give the answer january!

Nice try though.

Code:

/******************************
* C Program Code::Blocks v1.3 *
* Written by: EvoTone         *
* Date: Sept., 2006           *
*******************************/
#include <stdio.h>

typedef struct /*This structs DATE_RANGE w/ 2 constants num, char */
{
    const int lower; /*Defines a number as lower*/
    const char * month; /*Defines month names*/
} DATE_RANGE; /*Name of the struct*/

static const DATE_RANGE date_range[] =
{
    { 335, "December"  },
    { 305, "November"  },
    { 274, "October"   },
    { 244, "September" },
    { 213, "August"    },
    { 182, "July"      },
    { 152, "June"      },
    { 121, "May"       },
    {  91, "April"     },
    {  59, "March"     },
    {  31, "February"  },
    {   0, "January"   }
};

int main(void)
{
    int i;
    int julian; /*input value from user, needing conversion.*/

    /*Intro. & Instructions*/
    printf("This is a Julian to Calendar Date conversion program\n");
    printf("you may input any Julian date and the corresponding\n");
    printf("Calendar Date will be calculated for you\n\n");

                             /*Input Section*/
    printf("Please enter the Julian date: (whole number format)\n");
    scanf("%i", &julian);
    printf("Well silly we know it's Year: 2006!\n\n");


                            /*Calculation Section*/

    if ( (julian < 1) || (julian > 365) )
    {
        printf("Don't mess with me stupid!!...Julian Dates are only 1-365!\n");
        return(1);
    }

    for (i = 0; i < (sizeof(date_range) / sizeof(date_range[0])); i++)
    {
        if (julian > date_range[i].lower)
        {
            printf("And we know it's: %s\n", date_range[i].month);
            break;
        }
    }

    return (0);

}

Or (more obtusely), and less portable, but shorter and leap-year compliant!

Code:

/******************************
* C Program Code::Blocks v1.4 *
* Written by: EvoTone         *
* Date: Sept., 2006           *
*******************************/
#include <stdio.h>
#include <time.h>

int main(void)
{
    int julian; /*input value from user, needing conversion.*/
    time_t t;
    struct tm * ptm;
    char date_str[ 50 ];

    /* Introduction & Instructions */

    printf("This is a Julian to Calendar Date conversion program\n");
    printf("you may input any Julian date and the corresponding\n");
    printf("Calendar Date will be calculated for you\n\n");

    /* Input Section */

    printf("Please enter the Julian date: (whole number format)\n");
    scanf("%i", &julian);

    /* Calculation Section */

    if ( (julian < 1) || (julian > 365) )
    {
        printf("Don't mess with me stupid!!...Julian Dates are only 1-365!\n");
        return(1);
    }

    t = time( (time_t *) NULL );  /* Today's date/time */

    ptm = localtime( &t );

    if ( ptm != NULL )
    {
        ptm->tm_mday = 1; /* 1st of month */
        ptm->tm_mon  = 0; /* January      */

        /* Add "julian - 1" days to start of year */
        t = mktime( ptm ) + ( (julian - 1) * 24 * 60 * 60);

        if ( t >= 0 )
        {
            ptm = localtime( &t );

            if ( ptm != NULL )
            {
                /* Convert to string in format "Monday January 01 2006" */
                if ( strftime(date_str, sizeof(date_str), "%A %B %d %Y", ptm) != 0)
                    printf("And we know it's: %s\n", date_str);
            }
        }
    }

    return (0);
}

You only need to test for either the upper or the lower bound, and as the loop breaks out afterwards it will not continue.

You are right I found that I can test for the upper value but, the lower doesn't seem to work due to the fact that "January" is displayed everytime julian is greater than i.

Thanks guys!! I have learned a lot.... I am still to unexperienced to worry about leap years yet but, I have enough with the code still needing to define the days of the month compared to the days of a calendar year. After all I am trying to convert a "Julian Date" into a 200x/January/2 format. I'm sure as I head into this next phase of the project I will have more questions. For now thanks to all who helped out.

~EvoTone~

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