C language implementation of binary file read and write detailed

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)