Data saving issue in file - c

Question

I'm trying to write phone book program.I completed the first function(which saves knowledge). Program is running. However, after I enter the person's knowledge from keyboard and close the program it shows me just the last person's knowledge in file. I am using the program w mode, I tried w+ mode, too. But the problem still didn't change. For example as I use the first function I enter three people's knowledge but it shows me just one. How can I solve this ?
#include <stdio.h>
#include <stdlib.h> // "stdlib" library contains of exit() and malloc function
#include <Windows.h> // "Windows" library contains of Sleep() function which waits the system as you want
struct personKnowledge
{
char number[16];
char name[16];
char surname[16];
};
void newRecord();
void display();
void deletE();
void add();
void update();
FILE *ptrFILE;
int main()
{
int choice;
do
{
printf("\n\t\t *-* Phone Book Program *-*");
printf("\n\n\t\t 1) New record"); // The options are being presented to user
printf("\n\n\t\t 2) Display person knowledge");
printf("\n\n\t\t 3) Delete someone");
printf("\n\n\t\t 4) Add new person");
printf("\n\n\t\t 5) Update person knowledge");
printf("\n\n\t\t 6) Exit");
printf("\n\n\nEnter your choice: ");
scanf("%d", &choice);
switch (choice)
{
case 1:
{
newRecord();
break;
}
case 2:
{
break;
}
case 3:
{
break;
}
case 4:
{
break;
}
case 5:
{
break;
}
case 6:
{
printf("\nWorking has been completed.\n");
exit(EXIT_SUCCESS);
break;
}
default:
{
printf("\nWrong entry! The program has been terminated.\n");
break;
}
}
} while (choice >= 1 && choice <= 6);
return 0;
}
void newRecord()
{
system("cls"); // Screen is being cleaned
if ((ptrFILE = fopen("Phone Book.txt", "w")) == NULL)
{
printf("The file couldn't open\n");
}
else
{
struct personKnowledge *p; // p means person
p = (struct personKnowledge *)malloc(sizeof(struct personKnowledge)); // Memory is being allocated
fflush(stdin);
printf("\n\nDetermine person name: "); // User is entering the person's knowledge and they are being saved in file
gets(p->name);
printf("Determine %s's surname: ", p->name);
gets(p->surname);
printf("Determine %s's number: ", p->name);
gets(p->number);
fprintf(ptrFILE, "Name\t\t\t\tSurname\t\t\t\tNumber\n");
fprintf(ptrFILE, "--------\t\t ----------------\t\t------------------------\n");
fprintf(ptrFILE, "\n%s%33s%38s\n", p->name, p->surname, p->number);
free(p);
printf("Please wait, information is saving to file..\n");
Sleep(750);
printf("*-* Saving operation has been completed. *-*");
}
fclose(ptrFILE);
}

Answer 1

You are using write mode to write output to an already existing file. To preserve it's contents, use append modes like a or a+. For example
FILE * ptrFILE = fopen("Phone Book.txt", "a");
The description of other modes (may not be compatible with all platforms):
r or rb - Open file for reading.
w or wb - Truncate to zero length or create file for writing.
a or ab - Append; open or create file for writing at end-of-file.
r+ or rb+ or r+b - Open file for update (reading and writing).
w+ or wb+ or w+b - Truncate to zero length or create file for update.
a+ or ab+ or a+b - Append; open or create file for update, writing at end-of-file.

Answer 2

You should open it in append mode. Try this: if ((ptrFILE = fopen("Phone Book.txt", "a")) == NULL) Append mode will add contents to the end of your existing file contents.

Answer 3

If you open in write mode ("w" or "w+"), the last text is saved in file, but if you will open in append mode ("a" or "a+"), your file will include all of your writing.

Answer 4

Well in above mentioned programs-
Fisrt Program always enters the last record you enetres as you opened file in "w" mode and you call function void newRecord() again to enter another record thus closing file then again opening it. As already contains data you want next record after it but as file is opened in "w" mode it discards already present data in file and the file is treated as a new empty file.
In second program you mentioned in your answer is just main function thus not causing opening and closing of file again and again. That is why it normally saves your data.
Use "a" or "a+" mode to make your first program work normally.

Answer 5

No need a or a+ mode. I insist :) Here are new codes. The problem has been solved.
#include <stdio.h>
#include <stdlib.h> // "stdlib" library contains of exit() and malloc function
#include <Windows.h> // "Windows" library contains of Sleep() function which waits the system as you want
struct personKnowledge
{
char number[16];
char name[16];
char surname[16];
};
void newRecord(FILE *);///
void display();
void deletE();
void add();
void update();
FILE *ptrFILE;
int main()
{
int choice;
if ((ptrFILE = fopen("Phone Book.txt", "w+")) == NULL)
{
printf("The file couldn't open\n");
}
do
{
printf("\n\t\t *-* Phone Book Program *-*");
printf("\n\n\t\t 1) New record"); // The options are being presented to user
printf("\n\n\t\t 2) Display person knowledge");
printf("\n\n\t\t 3) Delete someone");
printf("\n\n\t\t 4) Add new person");
printf("\n\n\t\t 5) Update person knowledge");
printf("\n\n\t\t 6) Exit");
printf("\n\n\nEnter your choice: ");
scanf("%d", &choice);
switch (choice)
{
case 1:
{
newRecord(ptrFILE);
break;
}
case 2:
{
break;
}
case 3:
{
break;
}
case 4:
{
break;
}
case 5:
{
break;
}
case 6:
{
printf("\nWorking has been completed.\n");
exit(EXIT_SUCCESS);
break;
}
default:
{
printf("\nWrong entry! The program has been terminated.\n");
}
}
} while (choice >= 1 && choice <= 6);
fclose(ptrFILE);
return 0;
}
void newRecord(FILE *ptrFILE)
{
static int counter = 0;
system("cls"); // Screen is being cleaned
struct personKnowledge *p; // p means person
p = (struct personKnowledge *)malloc(sizeof(struct personKnowledge)); // Memory is being allocated
fflush(stdin);
printf("\n\nDetermine person name: "); // User is entering the person's knowledge and they are being saved in file
gets(p->name);
printf("Determine %s's surname: ", p->name);
gets(p->surname);
printf("Determine %s's number: ", p->name);
gets(p->number);
if (counter == 0)
{
fprintf(ptrFILE, "Name\t\t\t\tSurname\t\t\t\tNumber\n");
fprintf(ptrFILE, "--------\t\t ----------------\t\t------------------------\n");
}
fprintf(ptrFILE, "\n%33s%33s%38s\n", p->name, p->surname, p->number);
printf("Please wait, information is saving to file..\n");
Sleep(750);
printf("*-* Saving operation has been completed. *-*");
counter++;
free(p);
}