fwrite() is an I/O function which is used to write number of objects of specific size from the specified stream to a character array. This function returns the number of objects written sucessfully to the array, if the "count" value differs from number of objects written, it indicates an error.

    size_t fwrite( const void *buf, size_t size, 
                        size_t count, FILE *stream);

   #include <stdio.h>
   int main() 
    {
      FILE * str = fopen ( "fwriteeg.txt" , "wb" );
      char buffer[] = { 'a' , 'b' , 'c' };
      fwrite (buffer , 1 , sizeof(buffer) , str );
      fclose (str);
      return 0;
    }

    abc

In the above example the function is used to write the contents of the character array "abc" into the text file.