Compares two values for equality and, if they are equal, replaces one of the values.
To answer TimwiTerby's question: The methods take three values (a, b and c) all of the same time - so there are several overloads. The call compares the value of parameter a with paramater c. If they are equal, then the value of a is replaced by the value of b. The method also returns the original value of a, if a and c are unequal or the new value of a if a and c are equal.I've posted some samples on the invidudual method pages to illustrate how these methods work.I think the writing on this page could be made clearer.