c++ 多继承，指针在堆上开完空间以后怎么销毁

Question

问题遇到的现象和发生背景

多继承，指针在堆上开完空间以后怎么销毁

问题相关代码，请勿粘贴截图

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string.h>
#include <string>
#include <memory>

using namespace std;//命名空间

class interface1
{
public:
    virtual void func1(int a, int b) = 0;
    virtual void func3(int a) = 0;
};

class interface2
{
public:
    virtual void func2(int a, double b) = 0;
};

class Child:public interface1, public interface2
{
public:
    virtual void func1(int a, int b)
    {
        cout << "func1" << endl;
        cout << a << "||" << b << endl;
    }
    virtual void func3(int a)
    {
        cout << "func3" << endl;
        cout << a << endl;
    }
    virtual void func2(int a, double b)
    {
        cout << "func2" << endl;
        cout << a <<  "||" << b << endl;
    }
};

void test(interface1* if1, interface2* if2)
{
    if1->func1(10, 20);
    if1->func3(10.5);
    if2->func2(200, 15.6);
    if (if1 != NULL)
    {
        delete if1;
        if1 = NULL;
    }
    if (if2 != NULL)
    {
        delete if2;
        if2 = NULL;
    }

}


int main(void)
{
    //Child child;
    //test(&child, &child);
    interface1* if1 = new Child;
    interface2* if2 = new Child;
    test(if1, if2);
    if1 = NULL;
    if2 = NULL;
    return 0;
}

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

Answer 1

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string.h>
#include <string>
#include <memory>
using namespace std;//命名空间
class interface1
{
public:
    virtual void func1(int a, int b) = 0;
    virtual void func3(int a) = 0;
    virtual ~interface1() {}
};
class interface2
{
public:
    virtual void func2(int a, double b) = 0;
    virtual ~interface2() {}
};
class Child:public interface1, public interface2
{
public:
    virtual void func1(int a, int b)
    {
        cout << "func1" << endl;
        cout << a << "||" << b << endl;
    }
    virtual void func3(int a)
    {
        cout << "func3" << endl;
        cout << a << endl;
    }
    virtual void func2(int a, double b)
    {
        cout << "func2" << endl;
        cout << a <<  "||" << b << endl;
    }
};
void test(interface1* if1, interface2* if2)
{
    if1->func1(10, 20);
    if1->func3(10.5);
    if2->func2(200, 15.6);
    if (if1 != NULL)
    {
        delete if1;
        if1 = NULL;
    }
    if (if2 != NULL)
    {
        delete if2;
        if2 = NULL;
    }
}
 
int main(void)
{
    //Child child;
    //test(&child, &child);
    interface1* if1 = new Child;
    interface2* if2 = new Child;
    test(if1, if2);
    return 0;
}