Rosetta Code

Write entire file: Difference between revisions

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Write entire file (view source)

Revision as of 09:26, 17 September 2017

1,982 bytes added ,  6 years ago
→‎{{header|C}}: - fixed, moderate skill level
(→‎{{header|C}}: changed wording in the flag.)
(→‎{{header|C}}: - fixed, moderate skill level)
Line 80:
=={{header|C}}==
 
/*
{{improve|C| <br> [This ''improve'' flag was converted from an earlier attempt at flagging this entry for removal, see the ''history'' file.]
* Write Entire File -- RossetaCode -- ASCII version with BUFFERED files
<br><br> This is a simple example.
*/
<br><br> Wrong solution, written by someone who either does not know the language.
<br><br> My comment: undeclared/uninitialized filename and data.
<br><br> This solution should be removed from Rosetta Code. <br><br>}}
 
#define _CRT_SECURE_NO_WARNINGS
<lang c>#include <stdio.h>
#include <string.h>
 
#include <assert.h>
int main(void) {
#include <stdio.h>
FILE *foo =fopen(filename,"w");
#include <stdlib.h>
fwrite(data, strlen(data), 1, foo);
fclose(foo);
 
/**
return 0;
* Write entire file at once.
*
* @param fileName file name
* @param data buffer with data
* @param size number of bytes to write
*
* @return Number of bytes have been written.
*/
int writeEntireFile(char* fileName, const void* data, size_t size)
{
size_t numberBytesWritten = 0; // will be updated
 
// Notice: assertion can be turned of by #define NDEBUG
//
assert( fileName != NULL );
assert( data != NULL );
assert( size > 0 );
 
// Check for a null pointer and an empty file name.
//
// BTW, should we write if ( ptr != NULL) or simply if ( ptr ) ?
// Both of these forms are correct. At issue is which is more readable.
//
if ( fileName != NULL && *fileName != '\0' )
{
// Try to open file in BINARY MODE
//
FILE* file = fopen(fileName,"wb");
 
// There is a possibility to allocate a big buffer to speed up i/o ops:
//
// const size_t BIG_BUFFER_SIZE = 0x20000; // 128KiB
// void* bigBuffer = malloc(BIG_BUFFER_SIZE);
// if ( bigBuffer != NULL )
// {
// setvbuf(file,bigBuffer,_IOFBF,BIG_BUFFER_SIZE);
// }
 
if ( file != NULL )
{
// Return value from fwrite( data, 1, size, file ) is the number
// of bytes written. Return value from fwrite( data, size, 1, file )
// is the number of blocks (either 0 or 1) written.
//
// Notice, that write (see io.h) is less capable than fwrite.
//
 
if ( data != NULL )
{
numberBytesWritten = fwrite( data, 1, size, file );
}
fclose( file );
}
}
return numberBytesWritten;
}
 
#define DATA_LENGTH 8192 /* 8KiB */
 
int main(void)
{
// Large arrays can exhaust memory on the stack. This is why the static
// keyword is used.Static variables are allocated outside the stack.
//
static char data[DATA_LENGTH];
// Filling data array with 'A' character.
// Of course, you can use any other data here.
//
int i;
for ( i = 0; i < DATA_LENGTH; i++ )
{
data[i] = 'A';
}
 
// Write entire file at once.
//
if ( writeEntireFile("sample.txt", data, DATA_LENGTH ) == DATA_LENGTH )
return EXIT_SUCCESS;
else
return EXIT_FAILURE;
}
</lang>
Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/262778"