java - Methods using private members or public accessors -

i realize cannot answered, i'm looking whether there sort of guidance whether use private members directly or public accessors inside class methods.

for example, consider following code (in java, similar in c++):

public class matrix {      // private members     private int[][] e;     private int numrows;     private int numcols;      // accessors     public int rows(){ return this.numrows; }     public int cols(){ return this.numcols; }      // class methods     // ...     public void printdimensions()     {         // [a] using private members         system.out.format("matrix[%d*%d]\n", this.numrows, this.numcols);           // [b] using accessors         system.out.format("matrix[%d*%d]\n", this.rows(), this.cols());     } 

the printdimensions() function illustrates 2 ways same information, [a] using private members (this.numrows, this.numcols) or [b] via accessors (this.rows(), this.cols()).

on 1 hand, may prefer using accessors since there no way inadvertently change value of private member variables. on other, may prefer accessing private members directly in hopes remove unnecessary function call.

i guess question is, either de-facto standard or preferred?

it's style call. prefer use accessors, because imho function call overhead small enough in cases doesn't matter, , usage preserves data abstraction. if later want change way data stored, need change accessors, instead of hunting places touched variables.

i don't feel it, though, , break "rule" if thought had reason to.