Checking if a folder exists (and creating folders) in Qt, C++

To both check if it exists and create if it doesn't, including intermediaries:

QDir dir("path/to/dir");
if (!dir.exists())
    dir.mkpath(".");

To check if a directory named "Folder" exists use:

QDir("Folder").exists();

To create a new folder named "MyFolder" use:

QDir().mkdir("MyFolder");

When you use QDir.mkpath() it returns true if the path already exists, in the other hand QDir.mkdir() returns false if the path already exists. So depending on your program you have to choose which fits better.

You can see more on Qt Documentation