class point
时间: 2023-10-04 22:14:08 浏览: 52
`class point` 定义了一个点的数据类型。可能的实现如下:
```python
class Point:
def __init__(self, x, y):
self.x = x
self.y = y
```
这个 `Point` 类有一个构造函数 `__init__`,接受两个参数 `x` 和 `y`,并将它们存储在 `self.x` 和 `self.y` 中。这些变量可以通过点对象的属性访问。例如,创建一个 `Point` 对象并访问其属性:
```python
p = Point(3, 4)
print(p.x) # 输出 3
print(p.y) # 输出 4
```
相关问题
class Point private. int_xy public: Point & operator- - ();Point operator- -int); Please finish the definition of the operator overloading Point& Point:;operator--0 Point Point::opcrator- -(int)
Here is the completed definition of the operator overloading functions:
```c++
class Point {
private:
int _x;
int _y;
public:
Point(int x = 0, int y = 0) : _x(x), _y(y) {}
// Prefix decrement operator overloading
Point& operator--() {
_x--;
_y--;
return *this;
}
// Postfix decrement operator overloading
Point operator--(int) {
Point temp = *this;
_x--;
_y--;
return temp;
}
// Friend function to output Point objects
friend std::ostream& operator<<(std::ostream& os, const Point& p) {
os << "(" << p._x << ", " << p._y << ")";
return os;
}
};
int main() {
Point p(5, 7);
std::cout << "p = " << p << std::endl;
// Prefix decrement
--p;
std::cout << "--p = " << p << std::endl;
// Postfix decrement
Point q = p--;
std::cout << "q = " << q << std::endl;
std::cout << "p = " << p << std::endl;
return 0;
}
```
In this example, we overload both the prefix decrement operator (`--`) and the postfix decrement operator (`--int`). The prefix decrement operator returns a reference to the Point object after decrementing its `_x` and `_y` members. The postfix decrement operator returns a copy of the original Point object before decrementing its members.
We also define a friend function `operator<<` to output Point objects in a nice format. Using these operator overloading functions, we can easily manipulate Point objects using the decrement operators.
3. 假设有Point类定义如下,编写测试类TestPoint,在main方法中,创建若干个Point对象,分别调用setX、setY方法设置点的x、y值,并输出Point对象的个数。运行程序,记录程序输出结果。 class Point{ double x,y;
好的,我理解了你的问题。以下是回答:
你的第一个问题是关于Java编程的。你希望我解释如何创建一个测试类TestPoint,并在其main方法中创建多个Point对象,并设置它们的x和y值,并输出Point对象的数量。
首先,你需要定义一个Point类,如下所示:
```java
class Point {
double x, y;
void setX(double x) {
this.x = x;
}
void setY(double y) {
this.y = y;
}
}
```
接下来,你可以创建TestPoint类,并在其main方法中创建多个Point对象,如下所示:
```java
public class TestPoint {
public static void main(String[] args) {
Point p1 = new Point();
Point p2 = new Point();
Point p3 = new Point();
p1.setX(1.0);
p1.setY(2.0);
p2.setX(3.0);
p2.setY(4.0);
p3.setX(5.0);
p3.setY(6.0);
System.out.println("Number of Point objects created: " + Point.class.getDeclaredFields().length);
}
}
```
在这个示例中,我们创建了三个Point对象,并设置它们的x和y值。然后,我们使用反射获取Point类的所有字段,并输出Point对象的数量。
当你运行这个程序时,它应该输出以下内容:
```
Number of Point objects created: 2
```
这是因为Point类有两个字段,即x和y。因此,我们创建的三个Point对象共享这两个字段,因此只计算为两个对象。