cin and cout can be used for most I/O
One of the great strengths of C++ is that simple I/O is simple.
It seems like it should be obviously true, but Java sadly makes
simple I/O difficult. To input most values, just use cin (pronounced see-in)
and the >> operator. Similarly, for output use
cout (pronounced see-out) and the << operator. For example,
int x;
int y;
cin >> x >> y;
cout << "Sum = " << (x+y) << endl;
The input is treated as a stream of characters without regard to spacing
or lines.
It's also easy to read in a loop.
while (cin >> x) { // Reads until EOF
sum += x;
}
See
Reading individual characters and lines
Because the default stream I/O skips whitespace, to read all characters or to read lines, you
have to use some different functions. See
Reading text files
Reading text files is very easy. It's basically the same as reading from cin,
but you have
to define a new file input stream and "open" it with a file name.
See
Using strings as source and destination of I/O
You can easily use all of the stream I/O capabilities to "read" and "write" using strings.
This isn't so commonly done, but it can be very useful. See
Formatting output
The I/O manipulators can be used to format your output, eg, to choose field widths and
number of decimals printed. See