>>505
#define FILENAME_IN "birth_in.txt"
#define FILENAME_OUT "birth_out.txt"

#include <stdio.h>
#include <string.h>

typedef struct tagBIRTHDAY
{
    char num[4];
    char filler1[2];
    char name[8];
    char filler2[2];
    char month[4];
    char month_unit[2];
    char day[4];
    char day_unit[2];
    char crlf[1];
} BIRTHDAY;

void swap(BIRTHDAY *left, BIRTHDAY *right)
{
    BIRTHDAY tmp;

    memcpy(&tmp, left, sizeof(tmp));
    memcpy(left, right, sizeof(left));
    memcpy(right, &tmp, sizeof(right));
}