数据结构计算器

摘要
通过对栈的应用实现‘+’，‘-’，‘*’，‘/’的运算，还包括‘（’，‘）’的应用。

算法思想
要想实现计算器，我们可以首先把中缀表达式转化为后缀表达式，再计算中缀表达式的值。

代码实现

#include
#include
using namespace std;

typedef struct{
	int *top;
	int *base;
	int stacksize;
}Stack;

char m[7][7]={         //优先级的定义顺序
{'>','>','<','<','<','>','>'},
{'>','>','<','<','<','>','>'},
{'>','>','>','>','<','>','>'},
{'>','>','>','>','<','>','>'},
{'<','<','<','<','<','=','#'},
{'>','>','>','>','#','>','>'},
{'<','<','<','<','<','#','='},
};

int InitStack(Stack &s)//初始化栈 
{
	s.base=new int[100];
	s.top=s.base;
	s.stacksize=100;
	return 1;
}

int push(Stack &s,int e)//入栈 
{
	if(s.top-s.base==s.stacksize) return 0;
	*s.top++=e;
	return 1;
}

int pop(Stack &s) //消栈顶
{
	if(s.top==s.base) return 0;
	*--s.top;
	return 1;
}

int GetTop(Stack s)//取栈顶元素 
{
	if(s.top!=s.base)
	{
		return *(s.top-1);
	}
}

void Delete(Stack &s)//销栈 
{
	delete s.base;
}

int In(char ch)  //判断是否为符号
{
	switch(ch)
	{
		case '+': return 0;
		case '-': return 0;
		case '*': return 0;
		case '/': return 0;
		case '(': return 0;
		case ')': return 0;
		case '=': return 0;
	}
	return 1;
}

char cmp(char a,char b)//比较优先级
{
	int i=0,j=0;
	switch (a)
	{
	case'+': i = 0; break;
	case'-': i = 1; break;
	case'*': i = 2; break;
	case'/': i = 3; break;
	case'(': i = 4; break; 
	case')': i = 5; break;
	case'=': i = 6; break;
	}

	switch (b)
	{
	case'+': j = 0; break;
	case'-': j = 1; break;
	case'*': j = 2; break;
	case'/': j = 3; break;
	case'(': j = 4; break;
	case')': j = 5; break;
	case'=': j = 6; break;
	}
	return m[i][j];
}

//计算函数 
int count(int a,char c,int b)
{
	int s;
	switch(c)
	{
		case '+': 
			s=b+a;break;
		case '-': 
			s=b-a;break;
		case '*': 
			s=b*a;break;
		case '/': 
			if(a==0)
			{
				cout<<"计算式错误！！！"<>ch;
			}
			else
			{
				d=GetTop(num);
				e=d*10+(ch - '0');
				pop(num);
				push(num,e);
				cin>>ch;
			}
		}

		if(In(ch)==0)
		{
			switch(cmp(GetTop(ope),ch))
			{
				case '<':			//优先级大于直接入栈
					push(ope,ch);
					cin>>ch;
					break;
				case '>':			//优先级小于进行运算
					c=GetTop(ope);
					pop(ope);
					a=GetTop(num);
					pop(num);
					b=GetTop(num);
					pop(num);
					push(num,count(a,c,b));
					break;
				case '=':          //优先级等于销栈顶元素
					pop(ope);
					cin>>ch;
					break;
			}	
		}
	}
	s=GetTop(num);
	pop(ope);
	Delete(num);
	Delete(ope);
	return s;
}

int main()
{
	int s;
	s=computer();
	cout<