Use of "this". Advice?

[pauljohn32]

I'm better at Java and Objective-C than CPP, so I don't feel completely sure about whether this usage is good or bad.

I ran into a CPP project in which the authors profusely use "this" in methods. I'm concerned because I suspect all of these "this->" usages may make the program run more slowly. Here's an example of a constructor

Model::Model()
{
        this->lconditional = false;
        this->lneedChain = false;
        this->lneedScores = false;
        this->lneedDerivatives = false;
        this->lparallelRun = false;
        this->linsertDiagonalProbability = 0;
        this->lcancelDiagonalProbability = 0;
        this->lpermuteProbability = 0;
        this->linsertPermuteProbability = 0;
        this->ldeletePermuteProbability = 0;
        this->linsertRandomMissingProbability = 0;
        this->ldeleteRandomMissingProbability = 0;
        this->lsimpleRates = 0;
        this->lmodelType = NORMAL;
}

All of these variables are listed in the private section of the Model class's definition.

I think that all of these "this->" are not needed. All of those variables are instance variables, and inside the class's constructors and member functions, all of those variables are directly available.

Am I understanding "this" correctly?



pj

[firedraco]

It's exactly the same. If you don't put this-> the compiler will assume it if needed.

[coder777]

this is a parameter that is invisibly passed to each memberfunction. It is always used to access member variables whether written or not

[kbw]

You don't need to do that, and shouldn't unless there's a compelling reason to.

Perhaps you just need some naming convention to identify member data.

[jaded7]

Somewhat related point: you should use initializer lists where possible