计算器 - 栈的应用

头文件CHAR.H

#pragma once
#include<iostream>
#define OK 1
#define ERROR 0
using namespace std;
class CHAR
{
private:
	typedef struct StackNode
	{
		char data;
		struct StackNode *next;
	}*Stack;

public:
	Stack S = NULL;
	CHAR()
	{
		InitStack();
	}

	int InitStack()//初始化
	{
		S = NULL;
		return OK;
	}

	int Push(char e)//入栈
	{
		Stack p = new StackNode;
		p->data = e;
		p->next = S;
		S = p;
		return OK;
	}

	char Pop()//出栈
	{
		if (S == NULL) return ERROR;
		int e = S->data;
		Stack p = S;
		S = S->next;
		delete p;
		return e;
	}

	char GetTop()//获得栈顶元素
	{
		if (S == NULL) return ERROR;
		return S->data;
	}

	int StackEmpty()
	{
		if (S == NULL)
		{
			return 0;
		}
		else
		{
			return 1;
		}
	}


};

LINKSTACK.H

#pragma once
#include<iostream>
#define OK 1
#define ERROR 0
using namespace std;
class LinkStack
{
	private :
		typedef struct StackNode
		{
			int data;
			struct StackNode *next;
		}*Stack;

	public :
		Stack S = NULL;
		LinkStack()
		{
			InitStack();
		}

		int InitStack()//初始化
		{
			S = NULL;
			return OK;
		}

		int Push(int e)//入栈
		{
			Stack p = new StackNode;
			p->data = e;
			p->next = S;
			S = p;
			return OK;
		}

		int Pop()//出栈
		{
			if (S == NULL) return ERROR;
			int e = S->data;
			Stack p = S;
			S = S->next;
			delete p;
			return e;
		}

		int GetTop()//获得栈顶元素
		{
			if (S == NULL) return ERROR;
			return S->data;
		}

		int StackEmpty()
		{
			if (S == NULL)
			{
				return 0;
			}
			else
			{
				return 1;
			}
		}
		

};

#include"LinkStack.h"
#include"CHAR.h"
#include<iostream>
using namespace std;
int In(char ch)//判断是否为数字
{
	if (ch >= '0' && ch <= '9')
	{
		return 1;
	}
	return 0;
}

char Precede(char a, char b)
{
	char c;
	if (a == '#' && b != '#') c = '<';
	if (a == '#' && b == '#') c = '=';
	else if ( a == '+' || a == '-')
	{
		if (b == '+' || b == '-' || b == ')' || b == '#')
		{
			c = '>';
		}
		else
		{
			c = '<';
		}
	}
	else if (a == '*' || a == '/')
	{
		if (b == '(')
		{
			c = '<';
		}
		else
		{
			c = '>';
		}
	}
	else if (a == '(')
	{
		if (b == ')')
		{
			c = '=';
		}
		else if (b == '+' || b == '-' || b == '*' || b == '/' || b == '(')
		{
			c = '<';
		}
	}
	else if (a == ')')
	{
		if (b == '+' || b == '-' || b == '*' || b == '/' || b == ')')
		{
			c = '>';
		}
	}
	return c;
}

int Operate(int a, char b, int c)//运算函数
{
	int sum = 0;
	switch (b)
	{
		case '+':
			sum = a + c;
			break;
		case '-':
			sum = a - c;
			break;
		case '*':
			sum = a * c;
			break;
		case '/':
			sum = a / c;
			break;
		default:
			break;
	}
	return sum;
	return 0;
}


int main()
{
	LinkStack OPND;
	CHAR OPTR;
	int num = 0;
	OPTR.Push('#');
	char theta;//运算符
	int a, b;//运算数
	char ch;//输入
	cin >> ch;
	while (ch != '#' || OPTR.GetTop() != '#')
	{
		if (In(ch))
		{
			num = ((ch - '0') + num * 10);
			cin >> ch;
		}
		else
		{
			if (num != 0)
			{
				OPND.Push(num);
				num = 0;
			}
			switch (Precede(OPTR.GetTop(), ch))
			{
				case '<':
					OPTR.Push(ch);
					cin >> ch;
					break;
				case '>':
					theta = OPTR.Pop();
					b = OPND.Pop();
					a = OPND.Pop();
					OPND.Push(Operate(a, theta, b));
					break;
				case '=':
					OPTR.Pop();
					cin >> ch;
					break;
			}
		}
	}
	cout << OPND.GetTop();
	return 0;
}