When should you use the "this" keyword in C++?

Answer 1

When there is an ambiguity between, say, a function parameter and an instance variable.

Of course such ambiguity should be avoided! It might be preferable to change the function parameter name instead of incurring overhead (i.e. prefixes) for all access to instance parameters though...

Answer 2

Personally I never use this, except:

• when I need to pass 'this' as an argument to a method of another class
• in the implementation of the assignment operator

Answer 3

While this is a totally subjective question, I think the general C++ community prefers not to have this->. Its cluttering, and entirely not needed.

Some people use it to differentiate between member variables and parameters. A much more common practice is to just prefix your member variables with something, like a single underscore or an m, or m_, etc.

That is much easier to read, in my opinion. If you need this-> to differentiate between variables, you're doing it wrong. Either change the parameter name (from x to newX) or have a member variable naming convention.

Consistency is preferred, so instead of forcing this-> on yourself for the few cases you need to differentiate (note in initializer lists this is completely well-defined: x(x), where the member x is initialized by the parameter x), just get better variable names.

This leaves the only time I use this: when I actually need the address of the instance, for whatever reason.

Answer 4

It's usable when you have variables in a scope "above" the one you are working with.

int i;
public void foo() {
    int i;
    i = 3; // assign local variable
    this->i = 4; // assign global variable
}

Other than accessing variables in another scope, I myself agree with your "minimalistic choice". Less is more. :-)

Answer 5

I like to use it for clarification, as when accessing members that were inherited. It reminds the reader where the variable came from if you don't have a naming convention that conveys that information.

You must use the this pointer when:

• Returning the current object.
• Setting up relations between objects (passing this into a constructor or setter)
• Checking for self reference: this != argPtr

Answer 6

I can only recall doing it with

delete this;

Answer 7

For me, it depends. If it is a short function or variable, I just type it in (e.g. mCount). Most of the time, however, I use very descriptive member variable and function names (e.g. mExclusivelyLockedDigitalIOList ). In those instances, I tend to use the this pointer to have Visual Studio's IntelliSense finish my typing for me. Saves on keystrokes and spelling mistakes.