Mega Code Archive
Investigating the family
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/*
Beginning C, Third Edition
By Ivor Horton
ISBN: 1-59059-253-0
Published: Apr 2004
Publisher: apress
*/
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
char myfile[] = "C:\\myfile.bin"; /* Physical file name */
FILE *pfile = NULL; /* File pointer */
struct Date /* Structure for a date */
{
int day;
int month;
int year;
};
typedef struct family /* Family structure declaration */
{
struct Date dob;
char name[20];
char pa_name[20];
char ma_name[20];
}Family;
/* Function prototypes */
int get_person(Family *pfamily); /* Input function */
void show_person_data(void); /* Output function */
void get_parent_dob(Family *pfamily); /* Function to find pa & ma */
void main()
{
Family member; /* Stores a family structure */
Family *pmember = &member; /* Points to the family structure */
if((pfile = fopen(myfile, "wb")) == NULL)
{
printf("\nUnable to open %s for writing.\n", myfile);
abort();
}
while(get_person(pmember)) /* As long as we have input */
fwrite(pmember, sizeof member, 1, pfile); /* write it away */
fclose(pfile); /* Close the file now its written */
show_person_data(); /* Show what we can find out */
if(remove(myfile))
printf("\nUnable to delete %s.\n", myfile);
else
printf("\nDeleted %s OK.\n", myfile);
}
/* Function to input data on Family members */
int get_person( Family *temp)
{
static char more = '\0'; /* Test value for ending input */
printf("\nDo you want to enter details of a%s person (Y or N)? ",
more != '\0'?"nother " : "" );
scanf(" %c", &more);
if(tolower(more) == 'n')
return 0;
printf("\nEnter the name of the person: ");
scanf("%s", temp->name); /* Read the Family's name */
printf("\nEnter %s's date of birth (day month year); ", temp->name);
scanf("%d %d %d", &temp->dob.day, &temp->dob.month, &temp->dob.year);
printf("\nWho is %s's father? ", temp->name);
scanf("%s", temp->pa_name); /* Get the father's name */
printf("\nWho is %s's mother? ", temp->name);
scanf("%s", temp->ma_name); /* Get the mother's name */
return 1;
}
/* Function to output data on people on file */
void show_person_data(void)
{
Family member; /* Structure to hold data from file */
Family *pmember = &member; /* Pointer to Family structure */
fpos_t current = 0; /* File position */
pfile = fopen(myfile, "rb"); /* Open file for binary read */
/* Read data on person */
while(fread(pmember, sizeof member, 1, pfile))
{
fgetpos(pfile, ¤t); /* Save current position */
printf("\n\n%s's father is %s, and mother is %s.",
pmember->name, pmember->pa_name, pmember->ma_name);
get_parent_dob(pmember); /* Get parent data */
fsetpos(pfile, ¤t); /* Position file to read next */
}
fclose(pfile); /* Close the file */
}
/* Function to find parents' dates of birth. */
void get_parent_dob(Family *pmember)
{
Family testmem; /* Stores a relative */
Family *ptestmem = &testmem; /* Pointer to the relative */
int num_found = 0; /* Count of relatives found */
rewind(pfile); /* Set file to the beginning */
/* Get the stuff on a relative */
while(fread(ptestmem, sizeof(Family), 1, pfile))
{
if(strcmp(pmember->pa_name, ptestmem->name) == 0) /*Is it pa? */
{ /* We have found dear old dad */
printf("\n Pa was born on %d/%d/%d.",
ptestmem->dob.day, ptestmem->dob.month, ptestmem->dob.year);
if(++num_found == 2) /* Increment parent count */
return; /* We got both so go home */
}
else
if(strcmp(pmember->ma_name, ptestmem->name) == 0) /*Is it ma? */
{ /* We have found dear old ma */
printf("\n Ma was born on %d/%d/%d.",
ptestmem->dob.day, ptestmem->dob.month, ptestmem->dob.year);
if(++num_found == 2) /* Increment parent count */
return; /* We got both so go home */
}
}
}
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