fwrite

the program inputs data to an array of structures then prints out the results.. how could i create a function that would write the data to a file?
also how could i stop getting input if the user just hits return?


#include <stdio.h>

//structure to hold entries

struct entry {
char fname[15];
char lname[15];
char email[30];
};

struct entry list[20];

int x;

int main()
{

//loop to input data

for (x=0; x<20; x++)
{
printf("Enter first name: ");
scanf("%s", list[x].fname);
printf("Enter last name: ");
scanf("%s", list[x].lname);
printf("Enter Email adress: ");
scanf("%s", list[x].email);

}

printf("\n\n");

//loop to display data

for (x=0; x<20; x++)
{
printf("Name: %s %s", list[x].fname, list[x].lname);
printf("\t \tEmail: %s\n", list[x].email);
}

return(0);
}

For writing into a file you use command "fwrite" like this:

FILE *fin;

for (x=0; x<20; x++)
{
printf("Enter first name: ");
scanf("%s", list[x].fname);
printf("Enter last name: ");
scanf("%s", list[x].lname);
printf("Enter Email adress: ");
scanf("%s", list[x].email);
fin = fopen("File.dat", "ab");
fwrite(&list[x], sizeof(list[x]), 1, fin);
fclose(fin);
}

For reading from the file you use command "fread" like this:

for (x=0; x<20; x++)
{
fread(&list[x], sizeof(list[x]), 1, fin);
printf("Name: %s %s", list[x].fname, list[x].lname);
printf("\t \tEmail: %s\n", list[x].email);
}


That's all.

I would suggest writing and reading all 20 of the entries at once...

Code:

#include <stdio.h> 

//structure to hold entries 

struct entry { 
char fname[15]; 
char lname[15]; 
char email[30]; 
}; 

struct entry list[20]; 

int x; 

void getData (const char * fname)
{ 
 FILE * f ;
 //loop to input data 

 for (x=0; x<20; x++) 
 { 
  printf("Enter first name: "); 
  scanf("%s", list[x].fname); 
  printf("Enter last name: "); 
  scanf("%s", list[x].lname); 
  printf("Enter Email adress: "); 
  scanf("%s", list[x].email); 
 } 

 f = fopen (fname, "wb");
 fwrite (list, sizeof(list), 20, f);
 fclose (f);

 return;
}


void printData (const char * fname)
{

 FILE * f = fopen (fname, "rb");
 fread (list, sizeof (list), 20, f);
 fclose (f);

 //loop to display data 
 
 for (x=0; x<20; x++) 
 { 
  printf("Name: %s %s", list[x].fname, list[x].lname); 
  printf("\t \tEmail: %s\n", list[x].email); 
 } 

 return; 
}