C++ function to convert a date time value into different date formats

Introduction

A C++ function which takes standard time-stamp and a date-time format string(in which you wants the output) as input and format and returns the date in required format. 

Example:

• formatDateTime( tDepTime, "CCYY-MM-DD hh:mm:ss" ), Output: 2013-08-19 03:00:00 
• formatDateTime( tDepTime, "MMMM DD, CCYY - HH:mm:ss" ), Output: August 19, 2013 - 03:00:00  
• formatDateTime( tDepTime, "DDDD MMMM D, CCYY - HH:mm:ss" ), Output:  Monday  August 19, 2013 - 03:00:00 
• formatDateTime( tDepTime, "CCYY/MM/DD HH:mm:ss" ), Output: 2013/08/19 03:00:00  
• formatDateTime( tDepTime, "CCYYMMDDHHmm" ), Output: 201308190300 
• formatDateTime( tDepTime, "CCYYMMDDHHmm" ), Output: 20130819  
• formatDateTime( tDepTime, "MMDD" ), Output: 0819  

 etc.... 

Using the code 

char * FormatDateTime(__time32_t TimeStamp, char *pszFormatString)
{
    char pszRetBuf[100] = "";
    int iRetBufSize = 100; 

    struct tm today;
    if ( TimeStamp == 0x00 )
    {
        strcpy_s( pszRetBuf, iRetBufSize, "** No Date/Time **" );
        return pszRetBuf;
    }
    else
    {
        _localtime32_s( &today, &TimeStamp );
    }

    //In case you need whole month in output
    char szMonths[12][10]       = {"January","February","March","April",
      "May","June","July","August","September",
      "October","November","December"};
    char szShortMonths[12][4]   = {"Jan","Feb","Mar","Apr",
      "May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};
    char szShortMonths[12][4]   = {"Jan","Feb","Mar","Apr",
      "May","Jun","Jul","Aug",
      "Sep","Oct","Nov","Dec"};
    char szDays[7][10]          = {"Sunday","Monday","Tuesday",
      "Wednesday","Thursday","Friday","Saturday"};
    char szShortDays[7][4]      = {"Sun","Mon","Tue","Wed",
      "Thu","Fri","Sat"};
    char szAMPM[2][3]           = {"AM","PM"};
    int aiMnemonic[13]          = {2,2,2,2,2,4,2,4,3,2,4,3,2};
    char szMnemonics[13][5]     = {"hh","HH","mm","ss",
      "AP","CCYY","YY","MMMM",
      "MMM","MM","DDDD","DDD","DD"};
    char szMasks[13][5]         = {"%02d","%02d","%02d","%02d",
      "%s","%04d","%02d","%s","%s",
      "%02d","%s","%s","%02d"};
    int iYear = today.tm_year + 1900;
    if ( iYear < 1995 ) //|| iYear > 2030 )
        iYear = 0;
    int iMonth = today.tm_mon + 1;
    if ( iMonth < 1 || iMonth > 12 )
        iMonth = 0;
    int iDay = today.tm_mday;
    if ( iDay < 0 || iDay > 31 )
        iDay = 0;
    int iWeekDay = today.tm_wday;
    if ( iWeekDay > 6 )
        iWeekDay = 0;
    int iHour = today.tm_hour;
    int iMinute = today.tm_min;
    int iSecond = today.tm_sec;

    if ( iYear == 0 || iMonth == 0 || iDay == 0 )
    {
    strcpy_s( pszRetBuf, iRetBufSize, "** No Date/Time **" );
    return pszRetBuf;
    }

    void * vpReplace[13];
    vpReplace[0] = (void *)(( iHour > 12 ) ? iHour - 12 : iHour );
    vpReplace[1] = (void *)iHour;
    vpReplace[2] = (void *)iMinute;
    vpReplace[3] = (void *)iSecond;
    vpReplace[4] = ( iHour > 12 ) ? szAMPM[1] : szAMPM[0];
    vpReplace[5] = (void *)iYear;
    vpReplace[6] = (void *)(iYear - 2000);
    vpReplace[7] = szMonths[iMonth-1];
    vpReplace[8] = szShortMonths[iMonth-1];
    vpReplace[9] = (void *)iMonth;
    vpReplace[10] = szDays[iWeekDay];
    vpReplace[11] = szShortDays[iWeekDay];
    vpReplace[12] = (void *)iDay;

    char szDateOutput[1024];    // leave lots of working space!
    char szDateFormatTemp[20];
    memset( szDateOutput, 0x00, 1024 );

    // work from left to right, and replace characters as we find them.
    int iSource = 0;
    int iSourceLength = (int)strlen( pszFormatString );
    int iOutput = 0;
    int iMnemonic = 0;
    bool fReplaced;
    for ( iSource = 0; iSource < iSourceLength; iSource++ )
    {
        fReplaced = false;
        for ( iMnemonic = 0; iMnemonic < 13; iMnemonic++ )
        {
            if ( strncmp( &pszFormatString[iSource], 
                      szMnemonics[iMnemonic], aiMnemonic[iMnemonic] ) == 0 )
            {
                // since it matches - and since the order or length is reversed - go ahead and replace               
                sprintf_s( szDateFormatTemp, szMasks[iMnemonic], vpReplace[iMnemonic] );
                strcat_s( szDateOutput, szDateFormatTemp );
                iSource += ( aiMnemonic[iMnemonic] - 1 );
                fReplaced = true;
                iMnemonic = 20;
                iOutput = (int)strlen( szDateOutput );
                if ( iOutput > 900 )    // give ourselves breathing space!!!
                    ThrowException( "CCQData::formatDateTime", 
                      "Date Output Buffer in danger of causing memory exception", 3, __LINE__ );
                }
            }

        if (!fReplaced)
            szDateOutput[iOutput++] = pszFormatString[iSource];
    }

    strcpy_s( pszRetBuf, iRetBufSize, szDateOutput );
    return pszRetBuf;
}