C file handling program to Create Employee Record and Update it

\* C file handling program to Create Employee Record and Update it *\

# include < stdio.h >
# include < stdlib.h >
# include < string.h >
# define size 200
struct   emp
{

int id ; char *name ;

} *emp1, *emp3 ;

void   display( ) ;
void   create( ) ;
void   update( ) ;
FILE   *fp, *fp1 ;
int   count = 0 ;
int   main( )
{

int i, n, ch ;
char filename[20] ;
printf("\n Enter the filename to be opened : ") ;
scanf("%s", filename ) ;

printf("1] Create a Record\n") ;
printf("2] Display Records\n") ;
printf("3] Update Records\n") ;
printf("4] Exit") ;

while (1)
{
      printf("\nEnter your choice : ") ;
      scanf("%d", &ch ) ;

      switch (ch)
      {
            case 1 :
                  fp = fopen(filename, "a") ;
                  create() ;
                  break ;
            case 2 :
                  fp1 = fopen(filename, "rb" ) ;
                  display() ;
                  break ;
            case 3 :
                  fp1 = fopen(filename, "r+" ) ;
                  update() ;
                  break ;
            case 4 :
                  exit( 0 ) ;
      }
}
return 0 ;

}

/* To create an employee record */
void   create( )
{

int i ;
char *p ;
emp1 = (struct emp *)malloc(sizeof(struct emp)) ;
emp1->name = (char *)malloc((size)*(sizeof(char))) ;
printf("Enter name of employee : ") ;
scanf(" %[^\n]s", emp1->name ) ;
printf("Enter emp id : ") ;
scanf(" %d", &emp1->id ) ;
fwrite(&emp1->id, sizeof(emp1->id), 1, fp) ;
fwrite(emp1->name, size, 1, fp ) ;
// count to number of entries of records
count++ ;
fclose(fp) ;

}

/* Display the records in the file */
void   display( )
{

emp3 = (struct emp *)malloc(1*sizeof(struct emp)) ;
emp3->name = (char *)malloc(size*sizeof(char)) ;
int i = 1 ;
if ( fp1 == NULL )
      printf("\nFile not opened for reading") ;

while (i <= count)
{
      fread(&emp3->id, sizeof(emp3->id), 1, fp1) ;
      fread(emp3->name, size, 1, fp1) ;
      printf("\n%d %s",emp3->id,emp3->name ) ;
      i++ ;
}
fclose(fp1) ;
free(emp3->name) ;
free(emp3) ;

}

/* Update the employee record */
void   update( )
{

int id, flag = 0, i = 1 ;
char s[size] ;
if (fp1 == NULL)
{
      printf("File cant be opened") ;
      return ;
}

printf("Enter employee id to update : ") ;
scanf("%d", &id ) ;
emp3 = (struct emp *)malloc(1*sizeof(struct emp)) ;
emp3->name = (char *)malloc(size*sizeof(char)) ;

while( i <= count )
{
      fread( &emp3->id, sizeof(emp3->id), 1, fp1 ) ;
      fread( emp3->name, size, 1, fp1 ) ;
      if ( id == emp3->id )
      {
            printf("Enter new name of emplyee to update : ") ;
            scanf(" %[^\n]s", s ) ;
            fseek( fp1, -204L, SEEK_CUR ) ;
            fwrite( &emp3->id, sizeof(emp3->id), 1, fp1 ) ;
            fwrite( s, size, 1, fp1 ) ;
            flag = 1 ;
            break ;
      }
      i++ ;
}
if (flag != 1)
{
      printf("No employee record found") ;
      flag = 0 ;
}
fclose(fp1) ;
free( emp3->name ) ;
free( emp3 ) ;

}