C language implementation of binary file read and write detailed

Source: Internet
Author: User
Tags exit fread include printf

To introduce the function first, we will use three functions, Fopen,fread,fwrite. The order of binary reads and writes is to open the read-write file in binary mode with fopen, and then use the fread and fwrite two functions to write the data to the binary file. Let's take a look at the source of a copy program:

COPY.C:

#include <stdio.h>

#include <stdlib.h>
    
#define MAXLEN 1024
    
int main (int argc, char *argv[])
    
{
    
    if (argc < 3)
    
    {
    
        printf ("Usage:%s%s/n", argv[0], "infile outfile");
    
        Exit (1);
    
    }

    FILE * outfile, *infile;
    
    outfile = fopen (argv[2], "WB");
    
    infile = fopen (argv[1], "RB");
    
    unsigned char Buf[maxlen];
    
    if (outfile = null | | infile = null)
    
    {
    
        printf ("%s,%s", argv[1], "not exit/n");
    
        Exit (1);
    
    }   
    
       
    
    int RC;
    
    while (rc = fread (buf,sizeof (unsigned char), maxlen,infile)!= 0)
    
    {
    
        fwrite (buf, sizeof (unsigned char), RC, outfile);
    
}
    
Fclose (infile);
    
Fclose (outfile);
    
System ("PAUSE");
    
return 0;
}

Now to talk about this program, the role of the program is to copy the contents of file 1 directly to file 2, pay attention to the return value of fread, this value needs to be used in fwrite.

The following is a detailed description of the Fopen,fread,fwrite three functions.

fopen (Open file)

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