检查这段代码#include <iostream> using namespace std; class CmyPoint{ private: int x,y; public: CmyPoint(){cout<<"调用默认构造函数"<<endl;} CmyPoint(int,int); CmyPoint(const CmyPoint& p); ~CmyPoint(){cout<<"调用析构函数"<<endl;} int getx() { return x; } int gety() { return y; } }; CmyPoint::CmyPoint(int a,int b) { cout<<"调用默认构造函数"<<endl; x=a; y=b; } CmyPoint::CmyPoint(const CmyPoint& p) { cout<<"调用用于拷贝初始化的构造函数"<<endl; x=p.x; y=p.y; int main(){ CmyPoint point1; CmyPoint point2(1,2); CmyPoint point3(point1); return 0;}

这段代码存在一个错误：在`CmyPoint`类的默认构造函数中，应该初始化`x`和`y`的值。否则，创建一个`CmyPoint`对象时，`x`和`y`的值是未定义的，可能会导致程序出现未定义的行为。正确的默认构造函数应该是这样的：

CmyPoint() : x(0), y(0) {
    cout << "调用默认构造函数" << endl;
}

另外，这段代码在使用`CmyPoint`类中的拷贝构造函数时，没有使用`const`关键字修饰参数。正确的拷贝构造函数应该是这样的：

CmyPoint(const CmyPoint& p) {
    cout << "调用用于拷贝初始化的构造函数" << endl;
    x = p.x;
    y = p.y;
}

修改后的代码如下：

#include <iostream>
using namespace std;

class CmyPoint{
private:
    int x, y;
public:
    CmyPoint() : x(0), y(0) {
        cout << "调用默认构造函数" << endl;
    }
    CmyPoint(int, int);
    CmyPoint(const CmyPoint& p) {
        cout << "调用用于拷贝初始化的构造函数" << endl;
        x = p.x;
        y = p.y;
    }
    ~CmyPoint() {
        cout << "调用析构函数" << endl;
    }
    int getx() { return x; }
    int gety() { return y; }
};

CmyPoint::CmyPoint(int a, int b) {
    cout << "调用构造函数" << endl;
    x = a;
    y = b;
}

int main() {
    CmyPoint point1;
    CmyPoint point2(1, 2);
    CmyPoint point3(point1);
    return 0;
}