C++ 的哪些功能无法用 C 实现

C++ 是一种面向对象的编程语言，它是在 C 语言的基础上进行扩展而来的，因此大部分 C 语言的功能都可以在 C++ 中实现。然而，C++ 还引入了许多新的特性和功能，这些功能无法用 C 语言来实现。本文将讨论 C++ 的一些独有功能，并且给出相应的案例代码。

cpp
#include 
class Circle {
    private:
        double radius;
    public:
        Circle(double r) {
            radius = r;
        }
        double getArea() {
            return 3.14 * radius * radius;
        }
};
int main() {
    Circle c(5.0);
    std::cout << "Area: " << c.getArea() << std::endl;
    return 0;
}

cpp
#include 
class Animal {
    public:
        virtual void sound() {
            std::cout << "Animal makes a sound." << std::endl;
        }
};
class Dog : public Animal {
    public:
        void sound() {
            std::cout << "Dog barks." << std::endl;
        }
};
class Cat : public Animal {
    public:
        void sound() {
            std::cout << "Cat meows." << std::endl;
        }
};
int main() {
    Animal* animal1 = new Dog();
    Animal* animal2 = new Cat();
    animal1->sound();
    animal2->sound();
    delete animal1;
    delete animal2;
    return 0;
}

cpp
#include 
int divide(int a, int b) {
    if (b == 0) {
        throw "Division by zero!";
    }
    return a / b;
}
int main() {
    try {
        int result = divide(10, 0);
        std::cout << "Result: " << result << std::endl;
    } catch (const char* error) {
        std::cout << "Error: " << error << std::endl;
    }
    return 0;
}

cpp
#include 
template
T add(T a, T b) {
    return a + b;
}
int main() {
    int result1 = add(3, 5);
    double result2 = add(1.5, 2.5);
    std::cout << "Result 1: " << result1 << std::endl;
    std::cout << "Result 2: " << result2 << std::endl;
    return 0;
}