this指針

在D中每個對象都有通過一個名爲this指針,這個指針訪問它自己的地址。this 指針是一個隱含的參數，所有的成員函數。因此，一個成員函數內，this 可以用來指調用對象。

讓我們試試下面的例子就明白了this指針的概念：

import std.stdio; class Box { public: // Constructor definition this(double l=2.0, double b=2.0, double h=2.0) { writeln("Constructor called."); length = l; breadth = b; height = h; } double Volume() { return length * breadth * height; } int compare(Box box) { return this.Volume() > box.Volume(); } private: double length; // Length of a box double breadth; // Breadth of a box double height; // Height of a box } void main() { Box Box1 = new Box(3.3, 1.2, 1.5); // Declare box1 Box Box2 = new Box(8.5, 6.0, 2.0); // Declare box2 if(Box1.compare(Box2)) { writeln("Box2 is smaller than Box1"); } else { writeln("Box2 is equal to or larger than Box1"); } }

當上面的代碼被編譯並執行，它會產生以下結果：

Constructor called.
Constructor called.
Box2 is equal to or larger than Box1