// cxy1.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
/*--- birthday.c --------------------------- Listing 3-1 --------
 * Reads input file of birthdays and lists any duplicates.
 * Uses a simple hash table to identify the duplicates.
 *
 * Input records consists of lines of text of the form
 * MMDDName where MM = month, DD = day, Name. For example:
 *                  0212Abraham Lincoln
 * Note: for simplicity, no error checking is done on records.
 *-------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define TABLE_SIZE 366  /* Maximum days in a year */

FILE *fin;              /* Birthday file */
int  NameCount,         /* Number of names read */
     DupeCount;         /* Number of dupes found */

int hash_birthday ( char * );   /* Our hash function */

#ifdef __STDC__         /* in ANSI C, there's no strdup() */
/* the source code for this function is discussed in Ch. 2 */
char *strdup ( const char * );  /* string duplication */
#endif

int main (  )
{
    char buffer[128];   /* where the records will be read */
    int  hash_value;    /* the hash value we will compute */
    char *name;         /* pointer to birthday name       */

    char *Table[TABLE_SIZE];   /* table of birthday folks */
    int i;              /* subscript to init the table    */

    if (( fin = fopen ( "rt.txt", "rt" )) == NULL )
    {
       
        exit ( EXIT_FAILURE );
    }

    for ( i = 0; i < TABLE_SIZE; i++ )
          Table[i] = NULL;

    while ( ! feof ( fin ))
    {
        if ( fgets ( buffer, 128, fin ) == NULL )
            break;

        /* get rid of the '\n' at end of record */
        buffer [strlen ( buffer ) - 1] = '\0';

        NameCount += 1;

        hash_value = hash_birthday ( buffer );
        name = strdup ( buffer + 4 );

        if ( Table[hash_value] == NULL )  /* No duplicate, */
        {                                 /* so add name.  */
            Table[hash_value] = name;
            continue;
        }
        else
        {                                 /* Is duplicate, */
            DupeCount += 1;               /* so tell 'em.  */
            printf ( "%s and %s have the same birthday.\n",
                    name, Table[hash_value] );
            continue;
        }
    }

    if ( DupeCount == 0 )
    {
        printf ( "No duplicate matches found among %d people.\n",
                  NameCount );
        if ( NameCount > 50 )
            printf ( "How rare!\n" );
    }
    else
        printf ( "Among %d people, %d matches were found\n",
                NameCount, DupeCount );

    return ( EXIT_SUCCESS );
}

/*---------------------------------------------------------------
 * A simple hash algorithm. It converts the month and day
 * to the number of the day in the year. Adds the day in the
 * month to the number of days elapsed before that month began.
 *-------------------------------------------------------------*/
int hash_birthday ( char *data )
{
    const int days_elapsed[12] =
      { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };

    int mm, dd;
    char record [128];  /* where we store our copy of the data */

    strcpy ( record, data );  /* make our own copy */

    record [4] = '\0';  /* Mark the spot where the name begins */
    dd = atoi ( record + 2 );   /* Convert the day to an int */
    record [2] = '\0';  /* Mark off the spot where day begins */
    mm = atoi ( record );       /* Convert the month to an int */

    /* since mm is going to be an index into days_elapsed,
     * it must be checked for the correct range.
     */
    if ( mm < 1 || mm > 12 )
    {
        fprintf ( stderr, "Error in record for %s: %02d/%02d\n",
                 (char *) data + 4, mm, dd );
        exit ( EXIT_FAILURE );
    }

    return ( days_elapsed[mm - 1] + dd );
}

查詢生日同一天的程式碼

1017My sister
0212Abraham Lincoln
0704USA
0707Ringo Starr
0214St Valentine
0531Johnstown Flood of 1889
0725Andrea Doria sinks 1956
0728Plane hits Empire State Bldg 1945
0902Great Fire of London begins 1666
0911Hurricane Iniki 1992
1017San Francisco Quake 1989
0327My brother