//支持带括号的表达式,支持+-*/、^(指数)、取负、!(阶乘)
#include <iostream>
#include <stack>
#include <math.h>
usingnamespacestd;
doubleinStack();//核心函数，将操作符有序的入栈计算， 最后返回结果
voidcalculate(stack<char>& Ope, stack<double>& Num);//用来计算加减乘除, 结果放在数字栈顶
voidfactorial(stack<double>& Num);//用来计算阶乘
intpriority(charope_);//用来计算操作符的优先级
intmain() {
doubleresult;//最后的结果
cout <<"请输入：\n";
result = inStack();//将缓冲区的操作符和数字压入栈
cout <<"结果是：\n"<< result;
return0;
}
doubleinStack() {
stack<char> Ope;
stack<double> Num;
charope_;
doublenum_;
while(1) {
if(cin.peek() >='0'&& cin.peek() <='9') {//判断下一个是否是数字
cin >> num_;
Num.push(num_);//数字直接入栈
}
else{
cin >> ope_;
if(ope_ =='=') {
while(!Ope.empty()) calculate(Ope, Num);//如果符号栈不空，就一直计算
returnNum.top();//如果是等号且符号栈顶为空，就返回数字栈顶元素
}
elseif(ope_ =='!') factorial(Num);//如果是！就阶乘
elseif(ope_ =='('||Ope.empty()) Ope.push(ope_);//如果符号是左括号或符号栈为空直接压入
elseif(ope_ ==')') {//如果是右括号
while(Ope.top() !='(') calculate(Ope, Num);//一直计算完括号里的
Ope.pop();//左括号出栈
}
elseif(priority(Ope.top()) >= priority(ope_)) {//如果栈顶符号的优先级大于等于当前
calculate(Ope, Num);//计算结果压入数字栈,取出当前栈顶
Ope.push(ope_);//压入当前符号
}
elseOpe.push(ope_);//否则就压入符号栈
}
}
}
voidcalculate(stack<char>& Ope, stack<double>& Num) {
doublea, b;
if(Ope.top() =='-') {
a = Num.top(); Num.pop();
Ope.pop();//取出负号
Num.push(-a);//压入负值
if(!Num.empty()) {
if(Ope.empty() || Ope.top() !='(')
Ope.push('+');//如果前面还有数字，就压入+，即变成加负值
}
}
else{
a = Num.top(); Num.pop();
b = Num.top(); Num.pop();
if(Ope.top() =='+') Num.push(b + a);
elseif(Ope.top() =='*') Num.push(b * a);
elseif(Ope.top() =='/') Num.push(b / a);
elseif(Ope.top() =='^') Num.push(pow(b, a));
Ope.pop();
}
}
voidfactorial(stack<double>& Num) {
inta =static_cast<int>(Num.top());
intresult=1;
for(inti = 1; i <= a; i++) result *= i;
Num.push(static_cast<double>(result));
}
intpriority(charope_) {
if(ope_ =='(')return0;
elseif(ope_ =='+'|| ope_ =='-')return1;
elseif(ope_ =='*'|| ope_ =='/')return2;
elseif(ope_ =='^')return3;
}
| 