#include <iostream> using namespace std; class Base1 { protected: int data1; public: Base1(int a = 8) { data1 = a; cout << data1 << ", Base1 Constructor\n"; } ~Base1() { cout << data1 << ", Base1 Destructor\n"; } }; class Base2 { protected: int data2; public: Base2(int a = 9) { data2 = a; cout << data2 << ", Base2 Constructor\n"; } ~Base2() { cout << data2 << ", Base2 Destructor\n"; } }; class Derived :public Base1, public Base2 { int d; public: Derived(int x, int y, int z) : Base1(x), Base2(y) //A { d = z; cout << "Derived Constructor\n"; } ~Derived() { cout << "Derived Destructor\n"; } void Show() { cout << data1 << ',' << data2 << ',' << d << endl; } }; int main() { Derived c(1, 2, 3); c.Show(); return 0; }以上C++代码调试时显示有一个错误，怎么解决？

在代码的构造函数`Derived(int x, int y, int z) : Base1(x), Base2(y)`后面没有加上大括号`{}`，导致编译器无法正确识别构造函数的定义，因此报错。

正确的代码应该是：

#include <iostream>
using namespace std;

class Base1 {
protected:
    int data1;
public:
    Base1(int a = 8) {
        data1 = a;
        cout << data1 << ", Base1 Constructor\n";
    }
    ~Base1() {
        cout << data1 << ", Base1 Destructor\n";
    }
};

class Base2 {
protected:
    int data2;
public:
    Base2(int a = 9) {
        data2 = a;
        cout << data2 << ", Base2 Constructor\n";
    }
    ~Base2() {
        cout << data2 << ", Base2 Destructor\n";
    }
};

class Derived :public Base1, public Base2 {
    int d;
public:
    Derived(int x, int y, int z) : Base1(x), Base2(y) {
        d = z;
        cout << "Derived Constructor\n";
    }
    ~Derived() {
        cout << "Derived Destructor\n";
    }
    void Show() {
        cout << data1 << ',' << data2 << ',' << d << endl;
    }
};

int main() {
    Derived c(1, 2, 3);
    c.Show();
    return 0;
}

以上代码中，在`Derived`类定义后面加上了大括号`{}`，用于定义构造函数和析构函数的内容。这样就可以正确识别构造函数的定义，消除了编译器报错。