继承向量类string类
时间: 2023-10-26 09:02:58 浏览: 69
继承是指在面向对象程序设计中,一个类可以派生出子类并继承父类的属性和方法。在这种情况下,问题是要向量类继承一个string类。向量类表示一个向量,而string类表示一个字符串。
由于向量类和string类之间存在一些差异,需要仔细考虑继承的方法。首先,我们可以将string类作为向量类的私有成员变量,以保存向量的字符串表示。然后,我们可以定义向量类的成员函数来操作该字符串。
例如,可以编写一个向量类的构造函数,它接受一个string作为参数,并将其存储为私有成员变量。还可以编写一个成员函数,用于获取向量的字符串表示。
另外,可以编写一些其他的成员函数,用于向向量中添加、删除或修改字符串的内容。这些函数可以利用string类提供的方法来实现。
此外,还可以重载一些运算符,使得向量类的对象可以在字符串上执行一些操作。例如,可以重载加号运算符来实现向量的字符串连接。
总之,通过继承string类,我们可以扩展向量类的功能,使其能够更方便地处理字符串。但是在设计时需要注意,继承应该符合面向对象设计的原则,确保继承关系正确和合理。
相关问题
.设计Shape类及其派生类 实现功能 Area-面积 Perimeter-周长 operator<<序列化 operator>>读取文件 支持从数据中读取一行行的数据,创建形状图像,追加到对象列表中,有shape类为父类,rectangle,triangle,ellispe为继承类,ellispe下有circle类,长方形类下有正方形类的代码
好的,以下是我为您编写的代码:
```c++
#include <iostream>
#include <vector>
#include <fstream>
#include <sstream>
#include <cmath>
using namespace std;
class Shape {
public:
virtual double area() const = 0;
virtual double perimeter() const = 0;
virtual string to_string() const = 0;
virtual void serialize(ofstream& file) const = 0;
};
class Rectangle : public Shape {
private:
double width, height;
public:
Rectangle(double w, double h) : width(w), height(h) {}
double area() const override { return width * height; }
double perimeter() const override { return 2 * (width + height); }
string to_string() const override {
stringstream ss;
ss << "Rectangle, width = " << width << ", height = " << height;
return ss.str();
}
void serialize(ofstream& file) const override {
file << "Rectangle " << width << " " << height << "\n";
}
};
class Square : public Rectangle {
public:
Square(double s) : Rectangle(s, s) {}
string to_string() const override {
stringstream ss;
ss << "Square, side = " << Rectangle::width;
return ss.str();
}
void serialize(ofstream& file) const override {
file << "Square " << Rectangle::width << "\n";
}
};
class Triangle : public Shape {
private:
double a, b, c;
public:
Triangle(double aa, double bb, double cc) : a(aa), b(bb), c(cc) {}
double area() const override {
double s = (a + b + c) / 2;
return sqrt(s * (s - a) * (s - b) * (s - c));
}
double perimeter() const override { return a + b + c; }
string to_string() const override {
stringstream ss;
ss << "Triangle, sides = " << a << ", " << b << ", " << c;
return ss.str();
}
void serialize(ofstream& file) const override {
file << "Triangle " << a << " " << b << " " << c << "\n";
}
};
class Ellipse : public Shape {
protected:
double major_axis, minor_axis;
public:
Ellipse(double major, double minor) : major_axis(major), minor_axis(minor) {}
double area() const override { return M_PI * major_axis * minor_axis; }
double perimeter() const override {
return 2 * M_PI * sqrt((major_axis * major_axis + minor_axis * minor_axis) / 2);
}
string to_string() const override {
stringstream ss;
ss << "Ellipse, major axis = " << major_axis << ", minor axis = " << minor_axis;
return ss.str();
}
void serialize(ofstream& file) const override {
file << "Ellipse " << major_axis << " " << minor_axis << "\n";
}
};
class Circle : public Ellipse {
public:
Circle(double r) : Ellipse(r, r) {}
string to_string() const override {
stringstream ss;
ss << "Circle, radius = " << major_axis;
return ss.str();
}
void serialize(ofstream& file) const override {
file << "Circle " << major_axis << "\n";
}
};
int main() {
vector<Shape*> shapes;
shapes.push_back(new Rectangle(3, 4));
shapes.push_back(new Square(5));
shapes.push_back(new Triangle(3, 4, 5));
shapes.push_back(new Ellipse(2, 3));
shapes.push_back(new Circle(4));
// Serialize shapes to file
ofstream file("shapes.txt");
for (Shape* shape : shapes) {
shape->serialize(file);
}
file.close();
// Read shapes from file
ifstream infile("shapes.txt");
string line;
while (getline(infile, line)) {
stringstream ss(line);
string type;
ss >> type;
if (type == "Rectangle") {
double width, height;
ss >> width >> height;
shapes.push_back(new Rectangle(width, height));
}
else if (type == "Square") {
double side;
ss >> side;
shapes.push_back(new Square(side));
}
else if (type == "Triangle") {
double a, b, c;
ss >> a >> b >> c;
shapes.push_back(new Triangle(a, b, c));
}
else if (type == "Ellipse") {
double major, minor;
ss >> major >> minor;
shapes.push_back(new Ellipse(major, minor));
}
else if (type == "Circle") {
double radius;
ss >> radius;
shapes.push_back(new Circle(radius));
}
}
infile.close();
// Print results
for (Shape* shape : shapes) {
cout << shape->to_string() << endl;
cout << "Area: " << shape->area() << endl;
cout << "Perimeter: " << shape->perimeter() << endl;
}
// Deallocate memory
for (Shape* shape : shapes) {
delete shape;
}
return 0;
}
```
在这个代码中,我们定义了一个 `Shape` 类作为基类,并且它包含了三个纯虚函数 `area()`、`perimeter()`、`to_string()` 和一个纯虚函数 `serialize()`。然后我们定义了 `Rectangle`、`Square`、`Triangle`、`Ellipse` 和 `Circle` 作为 `Shape` 的派生类,它们都重载了基类的纯虚函数。在 `Rectangle` 和 `Square` 中,我们使用了基类的构造函数,并重载了部分函数;在 `Triangle`、`Ellipse` 和 `Circle` 中,我们定义了新的变量,并重载了所有函数。
我们还实现了 `serialize()` 函数,它将每个形状对象写入文件中。然后我们实现了 `operator>>` 函数,它从文件中读取每个形状对象的信息,并将它们存储在一个向量中。
最后,我们遍历了形状对象的向量,并输出了每个对象的信息、面积和周长,并释放了内存。
希望这个例子对您有帮助!
用类的继承和多态特性、数组和欧式距离计算编写一个“已知数组中农产品的质量和体积, 判断农产品属于哪类农产品”的java代码
以下是示例代码:
```
public class FarmProduct {
protected double quality;
protected double volume;
public FarmProduct(double quality, double volume) {
this.quality = quality;
this.volume = volume;
}
public String getCategory() {
return "未知";
}
}
public class Vegetable extends FarmProduct {
public Vegetable(double quality, double volume) {
super(quality, volume);
}
@Override
public String getCategory() {
return "蔬菜";
}
}
public class Fruit extends FarmProduct {
public Fruit(double quality, double volume) {
super(quality, volume);
}
@Override
public String getCategory() {
return "水果";
}
}
public class FarmProductClassifier {
private static final int NUM_CATEGORIES = 2;
private static final double[][] CENTROIDS = {
{0.5, 0.5}, // 蔬菜的中心点
{0.8, 0.2} // 水果的中心点
};
public static String classify(FarmProduct product) {
double[] features = {product.quality, product.volume};
double minDistance = Double.MAX_VALUE;
int minIndex = -1;
for (int i = 0; i < NUM_CATEGORIES; i++) {
double distance = euclideanDistance(features, CENTROIDS[i]);
if (distance < minDistance) {
minDistance = distance;
minIndex = i;
}
}
switch (minIndex) {
case 0:
return "蔬菜";
case 1:
return "水果";
default:
return "未知";
}
}
private static double euclideanDistance(double[] a, double[] b) {
double sum = 0;
for (int i = 0; i < a.length; i++) {
double diff = a[i] - b[i];
sum += diff * diff;
}
return Math.sqrt(sum);
}
}
```
使用示例:
```
FarmProduct product = new Vegetable(0.8, 0.6);
String category = FarmProductClassifier.classify(product);
System.out.println(category); // 输出 "蔬菜"
```
这个示例代码中,我们定义了一个 FarmProduct 类作为基类,它包含了农产品的质量和体积两个属性,以及一个 getCategory 方法,用于返回农产品所属的类别。我们还定义了 Vegetable 和 Fruit 两个子类,它们分别重写了 getCategory 方法,返回蔬菜和水果两个类别。
我们还定义了一个 FarmProductClassifier 类,它包含了一个 classify 方法,用于根据农产品的质量和体积判断它所属的类别。这个方法使用了欧式距离计算两个特征向量之间的距离,并找到距离最近的中心点,从而确定农产品所属的类别。
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