Question

关于C++中类的继承还有vector向量的问题，请问下面程序哪些地方出错了，应该怎么改

#include<iostream>
#include<vector>

class Base
{
public:
Base(int i)
{
foo = i;
}
virtual ~Base()
{}
void print()
{
std::cout<< foo << std::endl;
}
protected:
int foo;
private:
Base(const Base&rhs) : foo(rhs.foo){}
};

class A : public Base
{
public:
A(int i) :Base(i){}
};
int main( int argc, const char *argv[])
{
std::vector<A> foo;
foo.push_back(A(100));
foo.push_back(200);

for(size_t i = 0; i<foo.size(); ++i)
{
foo[i].print();
}
return 0;
}

Answer 1

#include<iostream>
#include<vector>

class Base
{
public:
    Base(){}
    Base(int i)
    {
        foo = i;
    }
    virtual ~Base()
    {}
    void print()
    {
        std::cout<< foo << std::endl;
    }
public:
    int foo;
private:
    Base(const Base&rhs) : foo(rhs.foo){}
};

class A : public Base
{
public:
    A(){}//无参构造函数
    A(int i) :Base(i){}
    A(const A&a){this->foo = a.foo;} //要赋值拷贝函数
};
int main( int argc, const char *argv[])
{
    std::vector<A> foo;
    foo.push_back(A(100));
    foo.push_back(A(200));

    for(size_t i = 0; i<foo.size(); ++i)
    {
        foo[i].print();
    }
    return 0;
}