C ++
我无法理解push和pop如何与栈一起工作。 我明白他们是如何工作的，因为他们推动一个号码让我们说到堆栈上，并且推出的最后一个号码将被弹出。 我也理解指针背后的逻辑以及它们如何工作。 我不明白的是代码应该如何编写。
我的程序应该让用户创建一个堆栈（确定它的大小），然后选择将堆栈上的内存（数字）推出或弹出。
这是我到目前为止，我卡住了。 我已经通过cplusplus.com进行了研究，并阅读了关于这些东西的几乎所有内容，但仍然无法弄清楚该程序应该如何布置以及如何运行。
#include<iostream>
#include<cstring>
#include<cmath>
#include<cstdlib>
using namespace std;
int choice;
int * arrPtr = NULL;
int * stack;
int * top;
int val, capacity, size;
//stack would point to the location of the first element,
// top would point to the location where the next element will be stored,
// capacity is the number of elements that can be stored in the stack,
// size would be the number of elements actually stored in the stack
int main()
{
//This is the menu
cout << "1. Create" << endl;
cout << "2. Push" << endl;
cout << "3. Pop" << endl;
cout << "4. Count" << endl;
cout << "5. Display" << endl;
cout << "6. Exitn" << endl;
cin >> choice;
//I figured i would use choices for the menu and went ahead and wrote it out
switch(choice)
{
case 1:
create();
break;
case 2:
push();
break;
case 3:
pop();
break;
case 4:
count(0);
break;
case 5:
display();
break;
case 6:
exit();
default:
cout << "Please enter correct choice (1-4)!";
break;
}
return 0;
} //end main
void create()
{
cout << "Enter the size of the stack you wish to create: ";
int capacity = 0;
cin >> capacity;
arrPtr = new int[capacity];
} //end create function
//From here it went wrong, I cannot figure it out.
void push(){
for (int i = 0; i < capacity; i++)
{
cout << "Enter the number you wish to put on the stack: ";
cin >> val;
push(val)
}//end for
}//end push
请帮我理解这一点。
创建std::array 。 创建迭代器。 将迭代器设置为数组的末尾。 （末尾含义是array.end() ）
推：递减迭代器，插入值。
Pop：返回值，递增迭代器。
计数：在堆栈上不是标准的，但你可以从最后减去当前的迭代器来获得它。
Peek：返回值
显然，你想确保你不会从阵列的前面推开，或者从后面弹出，所以你应该添加一些检查。
堆栈非常简单。 希望这可以帮助。
编辑：实现，未经测试的代码，有点流畅的想法
template <typename T, std::size_t N>
class Stack {
public:
Stack();
void push(T value);
T pop();
T peek() const;
std::size_t count() const;
private:
std::array<T, N> m_baseArray;
std::array<T>::iterator m_it;
};
template <typename T, std::size_t N>
Stack::Stack() : m_baseArray(), m_it(m_baseArray.end()) { }
template <typename T, std::size_t N>
void Stack::push(T value) {
if (m_it == m_baseArray.begin())
throw std::exception();
--m_it;
*m_it = value;
}
template <typename T, std::size_t N>
T Stack::pop() {
if (m_it == m_baseArray.end())
throw std::exception();
T res = *m_it;
++m_it;
return res;
}
template <typename T, std::size_t N>
T Stack::peek() const {
if (m_it == m_baseArray.end())
throw std::exception();
return *m_it;
}
template <typename T, std::size_t N>
std::size_t Stack::count() const {
return m_baseArray.end() - m_it;
}
最简单的堆栈使用std::vector
#include <iostream>
#include <vector>
using namespace std;
template<typename T>
class Stack{
private:
vector<T> theArray;
public:
Stack(){ theArray.clear(); }
void push(T data) { theArray.push_back(data); }
T pop() { T retData = theArray.back(); theArray.pop_back(); return retData; }
void display() {
for(size_t i = theArray.size() - 1; i != (size_t)-1; i--){
cout << theArray[i] << 'n';
}
}
};
int main(int argc, char *argv[])
{
Stack<int> s;
s.push(10);
s.push(20);
s.push(30);
s.display();
int ret = s.pop();
cout << "After popping : " << ret << 'n';
s.display();
return 0;
}
我已经在Mac上编译了这些代码，但它应该在装有bash的PC上的Linux上正常工作。
#include<iostream>
#include<cstring>
#include<cmath>
#include<cstdlib>
using namespace std;
int choice;
int capacity; /*size of stack*/
int stack[1000];/*THIS IS WHERE ALL THE STACK ENTRIES WILL BE STORED*/
int top=0; /* THIS WILL KEEP CHECK OF THE INDEX OF TOP MOST ELEMENT */
//stack would point to the location of the first element,
// top would point to the location where the next element will be stored,
// capacity is the number of elements that can be stored in the stack,
// size would be the number of elements actually stored in the stack
void create() //Set size of stack
{
cout << "Enter the size of the stack you wish to create: ";
cin >> capacity;
} //end create function
void push(int n) //Enter data into stack
{
/* Ensures that there isn't a stack overflow */
if(top<capacity)
{
stack[top++]=n;
}
else
{
cout<<"Stack FULL!!n";
}
//end for
}//end push
void pop() //Remove data from stack
{
/* Ensures that there isn't a stack underflow */
if(top>0)
{
cout<<"Popped entry is:"<<stack[top-1]<<"n";
top--;
}
else
{
cout<<"Stack is EMPTY!!n";
}
}
void count() //Count number of elements
{
cout<<"Stack size is:"<<top<<"n";
}
void display() //Print elements from lowest stack entry to highest
{
int i=0;
cout<<"Your stack is:n";
while(i<top)
{
cout<<i+1<<") "<<stack[i]<<"n";
i++;
}
}
int main()
{
system("clear"); //Start with blank screen
int exitCheck=1,entry;
//I figured i would use choices for the menu and went ahead and wrote it out -- This is good approach!!
cout<<"Welcome user n";
create(); /*Size of stack can be set only once to prevent inconsistency */
while(exitCheck == 1) /* This is the menu */
{
cout << "1. Push" << endl;
cout << "2. Pop" << endl;
cout << "3. Count" << endl;
cout << "4. Display" << endl;
cout << "5. Exitn" << endl;
cin >> choice; //Choice should be placed here as we need userinput during each turn
switch(choice)
{
case 1:
cout<< "Enter your data: ";
cin>>entry;
push(entry);
break;
case 2:
pop();
break;
case 3:
count();
break;
case 4:
display();
break;
case 5:
{
exitCheck=1;
break;
} /*exit in this case wont achieve a proper result in a concole based app thats why i replaced it with loop exit condition */
default:
cout << "Please enter correct choice (1-5)!n";
break;
}
cout<< "Enter 1 to continue else anything else to quit:n";
cin>> exitCheck;
}
cout<<"Thanks for using this code!!n";
return 0;
}
//end main
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