我正在尝试创建一个简单的洗牌和发牌模拟器。我使用一个 vector 来表示一副 52 张牌,每张牌都由结构 BitCard
表示,其元素的空间是内存,受位域限制。但是当构造函数尝试访问 vector 时,xCode 会抛出 BAD_ACCESS 异常:Thread 1: EXC_BAD_ACCESS (code =1 address = 0x0)
。我做了一些研究,发现这个异常与空指针链接,但似乎不知道如何修复它。我的代码如下:
#include <iostream>
#include <cctype>
#include <cstdlib>
#include <vector>
#include <iomanip>
using namespace std;
struct BitCard{
unsigned face:4;
unsigned color:1;
unsigned suit:2;
};
class DeckOfCards {
public:
static const int faces = 13;
static const int colors = 2;
static const int numberOfCards = 52;
DeckOfCards();
void shuffle();
void deal();
private:
vector <BitCard> deck={};
};
DeckOfCards::DeckOfCards(){
for (int i = 0; i <numberOfCards;++i){
deck[i].face = i%faces;
deck[i].suit = i/faces;
deck[i].color = i/(faces*colors);
}
}
void DeckOfCards:: shuffle(){
for (int i = 0; i <numberOfCards;i++){
int j = rand()%numberOfCards;
BitCard tmp = deck[i];
deck[i] = deck[j];
deck[j] = tmp;
}
}
void DeckOfCards:: deal(){
for (int k1 = 0, k2 = k1+numberOfCards/2;k1<numberOfCards/2-1;k1++,k2++)
{
cout << "Color:" << setw(3) << deck[k1].color
<< " Card:" << setw(3) << deck[k1].face
<< " Suit:" << setw(3) << deck[k1].suit
<< " Color:" << setw(3) << deck[k2].color
<< " Card:" << setw(3) << deck[k2].face
<< " Card:" << setw(3) << deck[k2].suit;
}
}
int main(int argc, const char * argv[]) {
DeckOfCards testDeck;
testDeck.shuffle();
testDeck.deal();
return 0;
}
异常是在行中生成的
deck[i].face = i%faces;
我该如何解决这个问题? 提前致谢!
最佳答案
您正在尝试在构造函数中访问 vector deck
的元素。但是当你调用构造函数时,你的deck
vector 是空的
vector <BitCard> deck={}; // <- empty deck
DeckOfCards::DeckOfCards(){
for (int i = 0; i <numberOfCards;++i){
deck[i].face = i%faces; // <- At construction time, you are trying to access deck with index i. but Deck is empty!
//...
}
}
一种解决方案是构造您的对象 BitCard
并将其推送到 vector
DeckOfCards::DeckOfCards(){
for (int i = 0; i <numberOfCards;++i){
BitCard myBitCard;
myBitCard.face = i%faces;
myBitCard.suit = i/faces;
myBitCard.color = i/(faces*colors);
deck.push_back(myBitCard);
}
}
关于c++ - 线程 1 : EXC_BAD_ACCESS (code =1 address = 0x0),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28637022/