fread function and fwrite function __ function

1. function function

used to read and write a block of data.

2. General calling Form

fread (BUFFER,SIZE,COUNT,FP);

fwrite (BUFFER,SIZE,COUNT,FP);

3. Notes

(1) Buffer: is a pointer, for fread, it is read into the data storage address. For Fwrite, the address of the data to be exported.

(2) Size: The number of bytes to read and write;

(3) Count: The number of bytes of data to be read and written;

(4) FP: file type pointer.

Note: 1 Completion of the fwrite () must be closed after the flow (fclose ());

2 after a read operation (Fread ()) is completed, if the stream is not closed (fclose ()), then the pointer (FILE * FP) automatically moves backwards the length of the previous read-write, does not close the stream, continues the next read operation, then the last output continues to output;

3 fprintf (): input to stream in format, its prototype is int fprintf (FILE *stream, const char *format[, argument, ...]); The usage is the same as printf (), but it is written to the stream instead of to the console. Note that the return value is the number of bytes written to the file for this operation. such as int c = fprintf (FP,%s%s%d%f, STR1,STR2, A, b), str1:10 byte; str2:10 byte; a:2 byte; B:8 Byte, C is 33, because a space is automatically added between different data at write time.

Be sure to close the file after it is used, or you will not be able to display the content correctly. Fwrite: Read two student information and use fwrite to file

Fread: Read the student information from the file with Fread.

fwrite.c

#include <stdio.h>
#define SIZE 2
struct Student_type
{
Char name[10];
int num;
int age;
Char addr[10];
}stud[size];
void Save ()
{
FILE *FP;
int i;
if ((Fp=fopen ("Stu_list", "WB")) ==null)
{
printf ("Cant open the file");
Exit (0);
}
for (i=0;i<size;i++)
{
if (fwrite (&stud[i],sizeof (struct student_type), 1,FP)!=1)
printf ("File Write error/n");
}
Fclose (FP);
}
Main ()
{
int i;
for (i=0;i<size;i++)
{
scanf ("%s%d%d%s", &stud[i].name,&stud[i].num,&stud[i].age,&stud[i].addr);
Save ();
}
for (i=0;i<size;i++)
{
printf ("%s,%d,%d", stud[i].name,stud[i].num,stud[i].age,stud[i].addr);
}
}

FREAD.C

#include <stdio.h>
#define SIZE 2
struct Student_type
{
Char name[10];
int num;
int age;
Char addr[10];
}stud[size];
void Read ()
{
FILE *FP;
int i;
if ((Fp=fopen ("Stu_list", "RB")) ==null)
{
printf ("Cant open the file");
Exit (0);
}
for (i=0;i<size;i++)
{
if (fread (&stud[i],sizeof (struct student_type), 1,FP)!=1)
printf ("File Write error/n");
}
Fclose (FP);
}
Main ()
{

int i;
Read ();
for (i=0;i<size;i++)
{
printf ("%s,%d,%d,%s", stud[i].name,stud[i].num,stud[i].age,stud[i].addr);
printf ("n");
}
}

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