c++ assignment

i got the first part done but i have second part that confuse me i have to write a write function that write in outputdata.dat all total of number in inputdata.dat.

here the code i got it work to display what inside inputdata.dat.

#include <iostream.h> #include <fstream.h> #include <stdlib.h> #define BUF_SIZE 21 #define IN_FILE "InputData.dat" extern void main( void ) { ifstream ifInputFile; ofstream stream; char sBuffer[BUF_SIZE]; bool bDataExists(true); ifInputFile.open("InputData.dat"); if( ifInputFile.is_open() != 1 ) { cout << "File " << IN_FILE << " could not be opened!" << endl; cout << "Exiting program, good bye." << endl; } else { while( bDataExists == true ) { ifInputFile.getline( sBuffer, 40 ); if( ifInputFile.eof() == 1 ) { bDataExists = false; } else { cout << sBuffer << endl; } } ifInputFile.close(); } }

here what it display

23
36
54
75
88
64

i have to write a code that add all this number and use write function to put it in output.dat file. It confuses me i get alot of errors. Thanks for helping me.