C Programming Code Examples

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Program Code - Investigating the family

Program Code - Investigating the family

#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[25];
   char pa_name[25];
   char ma_name[25];
}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    */
       }
   }
}