C++ 动态、基于数组的整数堆栈

Question

我刚刚开始学习 C++ 编程，为了锻炼我找到了这个任务。我必须编写一个动态的、基于数组的整数堆栈。这是我到目前为止所得到的。

    #include <iostream>

using namespace std;


class DynamicIntegerStack
{
private:
    int *bottom_;
    int *top_;
    int size_;
public:
    DynamicIntegerStack(int n = 20){
        bottom_ = new int[n];
        top_ = bottom_;
        size_ = n;
    }

    int getSize(){ return size_; }

    void push(int c){
        if (!full()){
            *top_ = c;
            top_++;
        }
        else{
            resize(size_ * 2);
            *top_ = c;
            top_++;
        }
    }

    void resize(int newSize){
        //Allocate new array and copy in data
        int *newArray = new int[newSize];
        memcpy(newArray, bottom_, size_);

        // Set the top to the new array
        top_ = newArray + (top_ - bottom_);

        // Delete old array
        delete[] bottom_;

        // Update pointers and size
        bottom_ = newArray;
        size_ = newSize;

        cout << "array has been resized" << endl;
    }

    int num_items() {
        return (top_ - bottom_);
    }
    char pop(){
        top_--;
        return *top_;
    }
    int full() {
        return (num_items() >= size_);
    }
    int empty() {
        return (num_items() <= 0);
    }
    void print(){
        cout << "Stack currently holds " << num_items() << " items: ";
        for (int *element = bottom_; element<top_; element++) {
            cout << " " << *element;
        }
        cout << "\n";
    }
    ~DynamicIntegerStack(){ // stacks when exiting functions
        delete[] bottom_;
    }
};
int main(){
    DynamicIntegerStack s(5);
    s.print(); cout << "\n";
    s.push(1); s.push(3); s.push(5); s.push(10); s.push(15);
    s.print(); cout << "\n";
    s.push(20);
    s.print(); cout << "\n";
    cout << "Popped value is: " << s.pop() << "\n";
    s.print(); cout << "\n";
    s.push(30);
    s.print(); cout << "\n";
    s.pop();
    s.pop();
    s.print(); cout << "\n";
    while (!s.empty()) s.pop();
    if (s.num_items() != 0) {
        cout << "Error: Stack is corrupt!\n";
    }
    s.print(); cout << "\n";
    // destructor for s automatically called
    system("pause"); // execute M$-DOS' pause command
    return 0;
}

它工作正常，直到数组已满并且我调整它的大小。之后它开始打印而不是整数。

预先感谢您的帮助。

Answer 1

当您使用memcpy 时，您正在复制的内存大小必须以字节为单位给出。

因此，您必须将 sizeof(int) 与您的 n 相乘。