下表显示了一元运算符，其目的列表。
| 函数名称 | 运算符 | 目的 |
|---|---|---|
| opUnary | - | 负数(数字补) |
| opUnary | + | 相同值(或者，副本) |
| opUnary | ~ | 按位取反 |
| opUnary | * | 访问指向 |
| opUnary | ++ | 自增 |
| opUnary | -- | 自减 |
一个例子如下，解释如何重载一个二元运算符。
| import std.stdio; |
| class Box |
| { |
| public: |
| double getVolume() |
| { |
| return length * breadth * height; |
| } |
| void setLength( double len ) |
| { |
| length = len; |
| } |
| void setBreadth( double bre ) |
| { |
| breadth = bre; |
| } |
| void setHeight( double hei ) |
| { |
| height = hei; |
| } |
| Box opUnary(string op)() |
| { |
| if(op == "++") |
| { |
| Box box = new Box(); |
| box.length = this.length + 1; |
| box.breadth = this.breadth + 1 ; |
| box.height = this.height + 1; |
| return box; |
| } |
| } |
| private: |
| double length; // Length of a box |
| double breadth; // Breadth of a box |
| double height; // Height of a box |
| }; |
| // Main function for the program |
| void main( ) |
| { |
| Box Box1 = new Box(); // Declare Box1 of type Box |
| Box Box2 = new Box(); // Declare Box2 of type Box |
| double volume = 0.0; // Store the volume of a box here |
| // box 1 specification |
| Box1.setLength(6.0); |
| Box1.setBreadth(7.0); |
| Box1.setHeight(5.0); |
| // volume of box 1 |
| volume = Box1.getVolume(); |
| writeln("Volume of Box1 : ", volume); |
| // Add two object as follows: |
| Box2 = ++Box1; |
| // volume of box2 |
| volume = Box2.getVolume(); |
| writeln("Volume of Box2 : ", volume); |
| } |
Volume of Box1 : 210 Volume of Box2 : 336
