14.3.8 Extracting Whitespace

By default, the iostream extractors skip leading whitespace. You can turn off the skip flag to prevent this from happening. The following example turns off whitespace skipping from cin, then turns it back on:

cin.unsetf(ios::skipws); // turn off whitespace skipping
...
cin.setf(ios::skipws); // turn it on again

You can use the iostream manipulator ws to remove leading whitespace from the iostream, whether or not skipping is enabled. The following example shows how to remove the leading whitespace from iostream istr:

istr >> ws;