Fread() and fwrite () function - c

Question

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <conio.h>
void delay (int milliseconds); // for delay function
void menu (); //for choosing a menu
void addacc(); // for adding account
void view (); // for viewing existing list
struct date
{
int date, month, year; //struct for date
};
struct customer
{
char name[40],acctype[10];
int accno, age;
double phone;
float amount;
struct date dob; //calling other struct inside struct
struct date deposit;
struct date withdraw;
} add; //struct variable
void addacc()
{
FILE *fp;
fp=fopen ("cus.txt", "a+");
textcolor (1);
printf ("\n\t\t\t\t");
cprintf ("ADD RECORD");
printf("\n\n\n");
printf ("Enter today's date(date/month/year) \n");
scanf ("%d/%d/%d", &add.deposit.date, &add.deposit.month,&add.deposit.year);
printf ("Enter account number\n");
scanf ("%d", &add.accno);
printf ("Enter customer's name\n");
scanf ("%s", add.name);
printf ("Enter customer's age\n");
scanf ("%d", &add.age); printf ("Enter customer's phone num\n");
scanf ("%f",&add.phone);
printf ("Enter the account type(in words): \n\t 1:Current\n\t 2:Saving\n\t 3:Fixed\n");
scanf ("%s",&add.acctype);
textcolor (2);
cprintf ("Almost done! Just enter the amount you want to deposit: ");
scanf ("%f",&add.amount);
fwrite (&add,sizeof(add),1,fp);
fclose (fp);
}
void view ()
{
FILE *view;
int test=0;
system ("cls");
textcolor (3);
printf ("\n\t\t\t\t");
cprintf ("Customer's List");
printf ("\n\n\n");
textcolor(4);
cprintf ("\tCustomer's Name:");
cprintf ("\tAccount Number:");
cprintf ("\tCustomer's Phone No:");
view=fopen("cus.txt", "r");
while(fread(&add, sizeof(add),1,view)!=0)
{
printf ("%s", add.name);
printf ("%d", add.accno);
printf ("%f", add.phone);
test++;
}
fclose (view);
if (test==0)
{
printf ("NO RECORDS FOUND!");
}
}
void menu ()
{
int n;
printf ("Enter your choice 1, 2\n");
scanf ("%d", &n);
switch (n)
{
case 1:
addacc();
break;
case 2:
view ();
break;
}
}
void main (void)
{
system ("cls");
menu ();
}
Output: when you choose 1 as option
ADD RECORD
Enter today's date
Enter customer's name
etc
output: when you choose option 2 for viewing the list of existing customers
screen blank
So I would like to know is my syntax of fread wrong or of fwrite? why isn't it showing on the screen the entries which I just entered? I am using fread function for reading structures into the file and then I want to print the entries on the screen.

Answer 1

I removed the Windows-specific code and cleaned things up a bit. The code religiously checks whether each scanf() returned the correct value; lazily, it just exits if it doesn't. It also checks that the calls to fopen() work.
Some of the scanf() calls were dodgy. You don't need the & in front of a string name, and you do need %lf to read a double (the phone number — interesting choice of data type). I made sure that newlines appear in the output.
The printing is a bit better, though there are problems of a sort with long names.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void menu(void); // for choosing a menu
void addacc(void); // for adding account
void view(void); // for viewing existing list
struct date
{
int date, month, year; // struct for date
};
struct customer
{
char name[40], acctype[10];
int accno, age;
double phone;
float amount;
struct date dob; // calling other struct inside struct
struct date deposit;
struct date withdraw;
} add; // struct variable
void addacc(void)
{
FILE *fp = fopen("cus.txt", "a+");
if (fp == NULL)
exit(1);
printf("ADD RECORD\n");
printf("Enter today's date(date/month/year) \n");
if (scanf("%d/%d/%d", &add.deposit.date, &add.deposit.month, &add.deposit.year) != 3)
exit(1);
printf("Enter account number\n");
if (scanf("%d", &add.accno) != 1)
exit(1);
printf("Enter customer's name\n");
if (scanf("%s", add.name) != 1)
exit(1);
printf("Enter customer's age\n");
if (scanf("%d", &add.age) != 1)
exit(1);
printf("Enter customer's phone num\n");
if (scanf("%lf", &add.phone) != 1)
exit(1);
printf("Enter the account type(in words): \n\t 1:Current\n\t 2:Saving\n\t 3:Fixed\n");
if (scanf("%s", add.acctype) != 1)
exit(1);
printf("Almost done! Just enter the amount you want to deposit: ");
if (scanf("%f", &add.amount) != 1)
exit(1);
fwrite(&add, sizeof(add), 1, fp);
fclose(fp);
}
void view(void)
{
FILE *view;
int test = 0;
printf("Customer's List\n");
printf("\tCustomer's Name:");
printf("\tAccount Number:");
printf("\tCustomer's Phone No:\n");
view = fopen("cus.txt", "r");
if (view == NULL)
exit(1);
while (fread(&add, sizeof(add), 1, view) != 0)
{
printf("\t%16s", add.name);
printf("\t%15d", add.accno);
printf("\t%20.0f", add.phone);
putchar('\n');
test++;
}
fclose(view);
if (test == 0)
{
printf("NO RECORDS FOUND!");
}
}
void menu(void)
{
int n;
printf("Enter your choice 1, 2\n");
if (scanf("%d", &n) != 1)
exit(1);
switch (n)
{
case 1:
addacc();
break;
case 2:
view();
break;
}
}
int main(void)
{
menu();
return 0;
}
Sample output:
Enter your choice 1, 2
2
Customer's List
Customer's Name: Account Number: Customer's Phone No:
BushraYousuf 12345678 112345987621
PresidentBarackObama 987654321 2021199920
He's got more money stashed away than you have.