我正在用C ++制作扑克游戏，我只是想开始吧。
我需要能够比较＆＃34; Hands＆＃34;，以查看哪一个更大，相等或更小。
所以，我现在有一个Hand类，我创建了另外两个名为Straight和ThreeOfKind的子类（稍后我会添加其余的子类）。
Hand类有一个名为compareTo(Hand* otherHand)的方法，然后检查手的排名以查看哪个更好。此外，对于Straights和Three of a Winds，当它们具有相同的等级时，您可以将它们进行比较。就像直道和三种有三种类型的直道。
我今天写了一些初始代码，问题是，当我试着打电话给＆＃34; Hand＆＃39;＆＃34; compareTo(Hand* otherHand)方法并传入Hand，Straight或Three of kind，编译器抱怨它试图强迫我使用Straight的compareTo(Straight* otherStraight)方法。所以，我应该超载，但它不起作用。
所以在继承完成后的Straight类中，我们应该有这两个方法：
int Hand::compareTo(Hand* otherHand);
int Straight::compareTo(Straight* otherStraight);
// But, if you do this, it works:
Straight myStraight1 = new Straight(7);
Straight myStraight2 = new Straight(5);
myStraight1.compareTo(myStraight2);
// This is valid...
// If you do this, then the compiler complains!
Straight myStraight3 = new Straight(10);
ThreeOfKind myTrips4 = new ThreeOfKind(3);
myStraight3.compareTo(myTrips4);
// This above line complains that you cannot convert a ThreeOfKind to a Straight
// Even though I am trying to use Hand's compareTo(Hand* otherHand) method and
// cast a Three of a Kind to a Hand object,
// it fails with the overloading!
以下是所有源代码......
//////////////////////////
// C++ main header file //
//////////////////////////
#pragma once
class Hand {
private:
int ranking;
public:
Hand(int aRanking);
Hand();
int getRanking();
int compareTo(Hand* otherHand);
};
class Straight : public Hand {
private:
int highCard;
public:
Straight(int aHighCard);
Straight();
int getHighCard();
int compareTo(Straight* otherStraight);
};
class ThreeOfKind : public Hand {
private:
int tripsValue;
public:
ThreeOfKind(int aTripsValue);
ThreeOfKind();
int getTripsValue();
int compareTo(ThreeOfKind* otherThreeOfKind);
};
///////////////////////////
// C++ main .cpp file... //
///////////////////////////
#include <iostream>
#include "PokerTest1.h"
using namespace std;
Hand::Hand(int aRanking) {
this->ranking = aRanking;
}
Hand::Hand() {
this->ranking = 0;
}
int Hand::getRanking() {
return this->ranking;
}
int Hand::compareTo(Hand* otherHand) {
cout << "COMPARING HANDS..." << endl;
if (this->getRanking() < otherHand->getRanking()) {
cout << "HANDS RETURNING -1..." << endl;
return -1;
}
else if (this->getRanking() > otherHand->getRanking()) {
cout << "HANDS RETURNING 1..." << endl;
return 1;
}
cout << "HAND RANKINGS ARE EQUAL..." << endl;
if (this->getRanking() == 4 && otherHand->getRanking() == 4) {
cout << "HANDS ARE BOTH STRAIGHTS..." << endl;
Straight* myStraight1 = (Straight*)this;
Straight* myStraight2 = (Straight*)otherHand;
cout << "COMPARING BOTH STRAIGHTS..." << endl;
return myStraight1->compareTo(myStraight2);
}
else if (this->getRanking() == 3 && otherHand->getRanking() == 3) {
cout << "HANDS ARE BOTH THREE OF A KINDS..." << endl;
ThreeOfKind* myTrips1 = (ThreeOfKind*)this;
ThreeOfKind* myTrips2 = (ThreeOfKind*)otherHand;
cout << "COMPARING BOTH TRIPS..." << endl;
return myTrips1->compareTo(myTrips2);
}
return 0;
}
Straight::Straight(int aHighCard) : Hand(4) {
this->highCard = aHighCard;
}
Straight::Straight() : Hand(4) {
this->highCard = 0;
}
int Straight::getHighCard() {
return this->highCard;
}
int Straight::compareTo(Straight* otherStraight) {
cout << "INSIDE STRAIGHT COMPARE TO..." << endl;
if (this->highCard < otherStraight->highCard) {
cout << "STRAIGHT COMPARE RETURNING -1..." << endl;
return -1;
}
else if (this->highCard > otherStraight->highCard) {
cout << "STRAIGHT COMPARE RETURNING 1..." << endl;
return 1;
}
cout << "STRAIGHT COMPARE RETURNING 0..." << endl;
return 0;
}
ThreeOfKind::ThreeOfKind(int aTripsValue) : Hand(3) {
this->tripsValue = aTripsValue;
}
ThreeOfKind::ThreeOfKind() : Hand(3) {
this->tripsValue = 0;
}
int ThreeOfKind::getTripsValue() {
return this->tripsValue;
}
int ThreeOfKind::compareTo(ThreeOfKind* otherThreeOfKind) {
cout << "INSIDE STRAIGHT COMPARE TO..." << endl;
if (this->tripsValue < otherThreeOfKind->tripsValue) {
cout << "TRIPS COMPARE RETURNING -1..." << endl;
return -1;
}
else if (this->tripsValue > otherThreeOfKind->tripsValue) {
cout << "TRIPS COMPARE RETURNING 1..." << endl;
return 1;
}
cout << "TRIPS COMPARE RETURNIN 0..." << endl;
return 0;
}
int main()
{
// Test the classes...
// with Straight compared to a Three of a Kind.
// Should try to invoke Hand::compareTo(Hand* otherHand) { ... };
// But, instead, it try to invoke Straight::compareTo(Straight* otherStraight) { ... };
// If you put both these methods in the Straight class (rather than using inheritence, it works)
// If you delete Straight::compareTo(Straight* otherStraight) { ... }, the line below compiles
// It is just strange why it won't compile...
Straight* myStraightA = new Straight(9); // Straight of 5, 6, 7, 8, 9
ThreeOfKind* myTripsB = new ThreeOfKind(2); // Three of a Kind of 2, 2, 2
cout << "Compare results..." << endl;
cout << myStraightA->compareTo(myTripsB) << endl; // Compiler error...
return 0;
}
此外，这里是手牌排名列表：
0 → high card
1 → pair
2 → two pair
3 → three of a kind
4 → straight
5 → flush
6 → full house
7 → quads
8 → straight flush
9 → royal flush
基本上我在Hand类中有一个字段，将这些排名存储为整数。你知道吗。
最后，这是编译器错误消息：
错误C2664：＆＃39; int Straight :: compareTo（Straight ）＆＃39;：无法从＆＃39; ThreeOfKind ＆＃39;转换参数1到＆＃39;直接*＆＃39;
答案 0 :(得分：3)
You are trying to overload across classes.
编译器查找compareTo方法，在Straight中找到它，但不查看Hand。如果您添加了适当的using语句，则可以告诉它查看Hand的compareTo以完成重载。
class Straight : public Hand {
private:
int highCard;
public:
using Hand::compareTo; // <<< HERE
Straight(int aHighCard);
Straight();
int getHighCard();
int compareTo(Straight* otherStraight);
};
我建议您使用getRanking()进行不同手牌类型之间的比较，而不是这样做，并定义由子类覆盖的getTieBreaker()来处理相同类型手牌的情况。
class Hand {
public:
int getRanking();
// virtual causes subclass' version to be called if done from reference or pointer.
virtual int getTieBreaker();
};
这简化了Hand比较的方式：
int Hand::compareTo(Hand* otherHand) {
if (this->getRanking() < otherHand->getRanking()) {
return -1;
}
else if (this->getRanking() > otherHand->getRanking()) {
return 1;
}
if (this->getTieBreaker() < otherHand->getTieBreaker()) {
return -1;
}
else if (this->getTieBreaker() > otherHand->getTieBreaker()) {
return 1;
}
return 0;
}
让你在Straight中定义它：
class Straight : public Hand {
//...
public:
int getHighCard();
int getTieBreaker();
};
int Straight::getTieBreaker() {
return this->highCard;
}