Question

我基本上试图通过将其传递给函数来反转堆栈。但是，当我运行程序时程序崩溃，我找不到逻辑错误，因为我甚至重载了赋值运算符来处理指针数据成员。

#include <iostream>

using namespace std;

/***************************************************************************/

class AStack {
public:
    AStack();
    AStack(int);
    ~AStack();
    AStack operator = (AStack s);
    void push(int);
    int pop();
    int top();
    bool isEmpty();
    void flush();

private:
    int capacity;
    int* a;
    int index = -1; // Index of the top most element
};

AStack::AStack() {
    a = new int[25];
    capacity = 25;
}

AStack::AStack(int size) {
    a = new int[size];
    capacity = size;
}

AStack::~AStack() {
    delete[] a;
}

AStack AStack::operator = (AStack s) {
    capacity = s.capacity;
    int* a = new int[capacity];
    for (int i = 0; i < capacity; i++) {
        a[i] = s.a[i];
    }
    index = s.index;
    return *this;
}

void AStack::push(int x) {
    if (index == capacity - 1) {
        cout << "\n\nThe stack is full. Couldn't insert " << x << "\n\n";
        return;
    }
    a[++index] = x;
}

int AStack::pop() {
    if (index == -1) {
        cout << "\n\nNo elements to pop\n\n";
        return -1;
    }
    return a[index--];
}

int AStack::top() {
    if (index == -1) {
        cout << "\n\nNo elements in the Stack\n\n";
        return -1;
    }
    return a[index];
}

bool AStack::isEmpty() {
    return (index == -1);
}

void AStack::flush() {
    if (index == -1) {
        cout << "\n\nNo elements in the Stack to flush\n\n";
        return;
    }
    cout << "\n\nFlushing the Stack:  ";
    while (index != -1) {
        cout << a[index--] << "  ";
    }
    cout << endl << endl;
}

/***************************************************************************/

void reverseStack(AStack& s1) {
    AStack s2;
    while (!s1.isEmpty()) {
        s2.push(s1.pop());
    }
    s1 = s2;
}

/***************************************************************************/

int main() {

    AStack s1;
    s1.push(1);
    s1.push(2);
    s1.push(3);
    s1.push(4);
    s1.push(5);
    reverseStack(s1);
    cout << "\n\nFlushing s1:\n";
    s1.flush();
    system("pause");
    return 0;
}

Answer 1

您没有提供复制构造函数，并且赋值运算符按值获取参数。语句s1 = s2通过调用隐式定义的复制构造函数来创建s2的副本，该复制构造函数复制指针，然后分配给s1。在表达式的末尾，副本被销毁，在指针上调用delete []。在函数结束时，s2的析构函数运行并再次尝试delete []相同的指针。

你需要提供一个能做正确事情的复制构造函数。

尽管没有逻辑错误，程序崩溃

1 个答案: