Teach Yourself Borland C++ in 14 Days - portal

124 Day 4
NOTE
One of the ifstream constructors takes a char* as a parameter so that you can provide a
filename when you instantiate the class. Using this constructor, lines 12 and 13 could be
condensed into a single line:
ifstream infile(“readfil.cpp”);
If you create the object this way, the call to open() is unnecessary because the file will
automatically be opened from the constructor.
TIP
Don’t forget about the double backslash in constant strings! For
example, if you wanted to open the WIN.INI file in the Windows
directory, you would have to use this:
ifstream infile(“c:\\windows\\win.ini”);
I know I’ve mentioned this before, but I’ll guarantee you that at some
point you’ll goof this up, so I want to drill it into your head while I’ve
got the opportunity.
The call to close() on line 19 of Listing 4.4 is not strictly needed. The ifstream destructor
checks whether the file was left open. If it was, the destructor calls close() to ensure that the
file is closed before the instance of the class is destroyed. In my programs I almost always call
close() even though it is not strictly required. Explicitly calling close() has the added benefit
of documenting that the file is no longer needed.
The program in Listing 4.4 contains a minor bug. Due to the way the
end of the file is determined, the program will print one blank line
before the loop terminates. In order to avoid the extra line, the loop
would have to be written like this:
while (!infile.getline(buff, sizeof(buff)).eof()) {
cout