C++数据结构——链栈（基本代码实现与案例）

Posted 2021-06-29 eyes++

一：基本代码实现

#include<iostream>
using namespace std;

enum error_code {
	success, underflow
};

struct node
{
	int data;
	node* next; // 指向下一结点
};

class linkStack {
public:
	linkStack();
	~linkStack();
	bool empty()const;
	error_code get_top(int& x)const;
	error_code push(const int x);
	error_code pop();
private:
	int count;
	node* top; // 指向自己
};

linkStack::linkStack()
{
	count = 0;
	top = NULL;
}

linkStack::~linkStack()
{
	while (!empty()) pop();
}

bool linkStack::empty()const {
	return count == 0;
}

error_code linkStack::get_top(int& x)const
{
	if (empty()) return underflow;
	x = top->data;
	return success;
}

error_code linkStack::push(const int x)
{
	node* s = new node;
	s->data = x;
	s->next = top;
	top = s;
	count++;
	return success;
}

error_code linkStack::linkStack::pop()
{
	if (empty()) return underflow;
	node* s = new node;
	s = top;
	top = s->next;
	delete s;
	count--;
	return success;
}

bool ReferenceError(error_code a)
{
	if(a == underflow){
		cout << "underflow!" << endl;
		return false;
	}
	return success;
}


int main()
{
	linkStack s;
	int top;
	
	for(int i = 0; i < 10; i++) // 入栈 
	    ReferenceError(s.push(i));
	for(int i = 0; i < 3; i++) // 出栈 
	    ReferenceError(s.pop());
	ReferenceError(s.get_top(top)); // 取栈顶
	
	cout << "栈顶元素：" << top << endl; 
	return 0;
}

二：链栈案例

• 案例一：设计算法将十进制转换为八进制
• 案例二：符号"{"，"}"，"["，"]"，"(",")"应该是互相匹配的，设计算法对以字符串形式读取的表达式S，判断其中的各括号是否是匹配的
• 案例三：使用栈结构写一个能计算带括号的四则表达式表达式的计算器

#include<iostream>
using namespace std;

enum error_code {
	success, underflow
};

template <class T>
struct node
{
	T data;
	node<T>* next;
};

template <class T>
class linkStack {
public:
	linkStack();
	~linkStack();
	bool empty()const;
	error_code getTop(T& x)const;
	error_code push(const T x);
	error_code pop();
private:
	T count;
	node<T>* top;
};

template <class T>
linkStack<T>::linkStack()
{
	count = 0;
	top = NULL;
}

template <class T>
linkStack<T>::~linkStack()
{
	while (!empty()) pop();
}

template <class T>
bool linkStack<T>::empty()const {
	return count == 0;
}

template <class T>
error_code linkStack<T>::getTop(T& x)const
{
	if (empty()) return underflow;
	x = top->data;
	return success;
}

template <class T>
error_code linkStack<T>::push(const T x)
{
	node<T>* s = new node<T>;
	s->data = x;
	s->next = top;
	top = s;
	count++;
	return success;
}

template <class T>
error_code linkStack<T>::linkStack::pop()
{
	if (empty()) return underflow;
	node<T>* s = new node<T>;
	s = top;
	top = s->next;
	delete s;
	count--;
	return success;
}

bool ReferenceError(error_code a)
{
	if (a == underflow) {
		cout << "underflow!" << endl;
		return false;
	}
	return success;
}

// 十进制转八进制
void transform()
{
	// 初始化题目条件 
	int num, result = 0;
	cout << "请输入要转化为八进制的十进制数：";
	cin >> num;
	
	// 初始化栈结构 
	linkStack<int>s;
	int top; 
	
	// 开始运算 
	while(num != 0)
	{
		s.push(num % 8);
		num /= 8;
	}
	while(!s.empty())
	{
		s.getTop(top);
		s.pop();
		result = result * 10 + top; 
	}
	cout << "转成八进制为：" << result << endl;
}

// 检验符号匹配
string symbol()
{
    // 初始化题目条件
	string s;
	cout << "请输入表达式S: ";
	cin >> s;
	int length;
	length = s.length();

	// 初始化栈结构
	linkStack<char>a;
	char top;
	 
	// 开始运算
	for(int i = 0; i < length; i++)
	{
		if(s[i] == '(' || s[i] == '[' || s[i] == '{')
		    a.push(s[i]);
		if(s[i] == ')')
		{
			a.getTop(top);
		    if(top == '(')
		        a.pop();
		    else
				return "不匹配！！";
		}
		if(s[i] == ']')
		{
			a.getTop(top);
		    if(top == '[')
		        a.pop();
		    else
		    	return "不匹配！！";
		}
		if(s[i] == '}')
		{
			a.getTop(top);
		    if(top == '{')
		        a.pop();
		    else
		    	return "不匹配！！";
		} 
	}
	return "匹配！！";
}

// 计算器
int getRes(int a, int b, char c) // 计算
{  
	int result;
	switch(c){
		case '+': result = a + b;
		    break;
		case '-': result = a - b;
		    break;
		case '*': result = a * b;
		    break;
		case '/': result = a / b;
		    break;
	}
	return result;
}
int getPri(char a) // 获得优先级 
{
	if(a == ')')
	    return 1; 
	if(a == '+' || a == '-')
	    return 2;
	if(a == '*' || a == '/')
	    return 3;
	if(a == '(')
	    return 4;
	else
		cout << "输入错误！！" << endl;
}
void calculator()
{
	// 初始化题目条件
	string s;
	cout << "请输入计算式：";
	cin >> s;
	int i = 0, k = 1, num1, num2;
	char sign;
	
	// 初始化栈结构
	linkStack<int>num;
	int top_n;
	linkStack<char>oper;
	char top_o;
	
	// 开始计算
	if(s[(s.length() - 1)] != '=')
	{
	    cout << "算式请以 '=' 结尾";
		return;	
	} 
	while(s[i] != '='){
		if(s[i] == '+' || s[i] == '-' || s[i] == '*' || s[i] == '/' || s[i] == '(' || s[i] == ')')
		{
			l:
			if(!oper.empty())
			{
				oper.getTop(top_o);
				if(getPri(s[i]) > getPri(top_o) || top_o == '(')
			        oper.push(s[i]);
				else
				{
				    oper.getTop(top_o);
				    if(top_o != '(')
				    {
						num.getTop(top_n);
				        num1 = top_n;
				        num.pop();
				        num.getTop(top_n);  
				        num.pop();
					    num.push(getRes(top_n, num1, top_o));
					    oper.pop();
					    oper.getTop(top_o);
					    if(top_o == '(')
					    {
						    oper.pop();
						    i++;
							continue;	
						}
					    goto l;  	
					}
			   }
		    }
			if(oper.empty())
		        oper.push(s[i]); 
	        k = 1;
	    }
		else
		{
			if(k == 0)
			{
				num.getTop(top_n);
				num.pop();
			    num.push(top_n * 10 + s[i] - 48);	
			}
			if(k == 1)
			{
			    num.push(s[i] - 48);
			    k = 0;
			}
		}
		i++;
	}
	
	num.getTop(top_n);
	num1 = top_n;
	num.pop();
	num.getTop(top_n);
	oper.getTop(top_o);
    cout << "计算结果为：" << getRes(top_n, num1, top_o) << endl;
}

int main()
{
	// 十进制转八进制
	transform();

	// 检验符号匹配
	cout << symbol() << endl;
	
	// 计算器
	calculator();

	return 0;
}