Function fwrite () in C

Function size_t fwrite (const void * ptr, size_t size, size_t nmemb, FILE * stream) in Standard C library writes data from the array pointed by ptr to the given Stream.

Declare the function fwrite () in C

Below is the declaration for the function fwrite () in C:

 size_t fwrite ( const void * ptr , size_t size , size_t nmemb , FILE * stream ) 

Parameters

ptr - This is the pointer to the array of items to be written.

size - This is the size (byte value) of each element written.

nmemb - This is the number of elements, with each element having the size of byte size.

stream - This is the pointer to a FILE object that defines an Output Stream.

Returns the value

This function returns the total number of elements returned successfully as a size_t object, which is an integer data type. If this number is different from the nmemb parameter, it will indicate an error.

For example

The following C program illustrates the usage of the function fwrite () in C:

 #include int main () { FILE * fp ; char str [] = "Hoc C co ban va nang cao tai QTM !!!" ; fp = fopen ( "baitapc.txt" , "w" ); fwrite ( str , 1 , sizeof ( str ) , fp ); fclose ( fp ); return ( 0 ); } 

Compiling and running the above program will create a baitapc.txt

Now monitor the above file contents by using the following C program:

 #include int main () { FILE * fp ; int c ; fp = fopen ( "baitapc.txt" , "r" ); while ( 1 ) { c = fgetc ( fp ); if ( feof ( fp ) ) { break ; } printf ( "%c" , c ); } fclose ( fp ); return ( 0 ); } 

Compile and run the above C program to see the results

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