#include <iostream>
#include<iomanip>
#define MAXSIZE 100
#define OK 1
#define ERROR 0
#define OVERFLOW - 2
using namespace std;
typedef struct { //运算符栈
char * base;
char * top;
int stacksize;
}
SqStack1;
int InitStack1(SqStack1 & S) { //运算符栈初始化
S.base = new char[MAXSIZE];
if (!S.base) return OVERFLOW;
S.top = S.base;
S.stacksize = MAXSIZE;
return OK;
}
int Push1(SqStack1 & S, char e) { //运算符栈入栈
if (S.top - S.base == S.stacksize) //栈满
return ERROR;
* S.top = e;
S.top++;
return OK;
}
int Pop1(SqStack1 & S) { //运算符栈出栈
if (S.top == S.base) //栈空
return ERROR;
S.top--;
return OK;
}
char GetTop1(SqStack1 S) { //运算符栈取栈顶元素
if (S.top != S.base)
return * (S.top - 1);
return ERROR;
}
typedef struct { //操作数栈
double * base;
double * top;
int stacksize;
}
SqStack2;
int InitStack2(SqStack2 & S) { //操作数栈初始化
S.base = new double[MAXSIZE];
if (!S.base) return OVERFLOW;
S.top = S.base;
S.stacksize = MAXSIZE;
return OK;
}
int Push2(SqStack2 & S, double e) { //操作数栈入栈
if (S.top - S.base == S.stacksize) //栈满
return ERROR;
* S.top = e;
S.top++;
return OK;
}
int Pop2(SqStack2 & S) { //操作数栈出栈
if (S.top == S.base) //栈空
return ERROR;
S.top--;
return OK;
}
double GetTop2(SqStack2 S) { //操作数栈取栈顶元素
if (S.top != S.base)
return * (S.top - 1);
return ERROR;
}
double Calculate(double a, char op, double b) { //计算表达式“a op b”的值
switch (op) {
case '+':
return a + b;
case '-':
return a - b;
case '*':
return a * b;
case '/':
return a / b;
}
}
char Precede(char a, char b) { //比较运算符a和b的优先级
if ((a == '(' && b == ')') || (a == '=' && b == '='))
return '=';
else if (a == '(' || a == '=' || b == '(' || (a == '+' || a == '-') && (b == '*' || b == '/'))
return '<';
else
return '>';
}
double Evaluateexpression(SqStack1 OPTR, SqStack2 OPND, char s[]) { //算术表达式求值的算符优先算法
/**************begin************/
/**************end************/
}
int main() { //设OPTR和OPND分别为运算符栈和操作数栈
SqStack1 OPTR;
InitStack1(OPTR); //初始化OPND栈
SqStack2 OPND;
InitStack2(OPND); //初始化OPTR栈
Push1(OPTR, '='); //将表达式起始符“=”压入OPTR栈
char s[100];
while (cin >> s) { //循环读入多组数据
if (s[0] == '=')
break; //当表达式只有一个“=”时，输入结束
//输出中缀算术表达式的值
cout << fixed << setprecision(2) << Evaluateexpression(OPTR, OPND, s) << fixed << setprecision(2) << endl;
}
return 0;
}
