cal

#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include<string.h>
#include<stdlib.h>


float num[101];
char ch[101];//符号
int numtop = -1;
int chtop = -1;

float cal(float a, float b, char c)//计算
{
	if (c == '+')
	{
		return a + b;
	}
	if (c == '-')
	{
		return a - b;
	}
	if (c == '*')
	{
		return a * b;
	}
	if (c == '/')
	{
		return a / b;
	}
}

int match(char a)//优先级打表（我是只会打表的菜狗
{
	if (a == '+' || a == '-')
		return 1;
	if (a == '*' || a == '/')
		return 2;
	if (a == '(' )
		return 0;
	
}
int chcmp(char a, char b)//优先级比较
{
	return (match(a) < match(b)) ? 0 : 1;
}

int ele(char c, int flag)//输入的c类型
{
	if (c <= '9' && c >= '0')//数字
	{
		if (numtop >= 0 && flag == 1)//不是第一个元素且上一个是数字
		{
			num[numtop] = num[numtop] * 10 + c - '0';//多位数
		}
		else
		{
			num[++numtop] = c - '0';//单个数字
		}
		return 1;
	}
	else if (c == '(')
	{
		ch[++chtop] = c;
		return 0;
	}
	else if (c == ')')
	{
		while (ch[chtop] != '(')//遍历到左括号
		{
			int numtop1 = numtop;
			numtop -= 1;
			int numtop2 = numtop;
			numtop -= 1;
			float temp = cal(num[numtop2], num[numtop1], ch[chtop--]);
			num[++numtop] = temp;
		}
		chtop--;
		return 0;
	}
	else if (c == '+' || c == '-' || c == '*' || c == '/')
	{
		if (chtop >= 0)
		{
			while (1 == chcmp(ch[chtop], c))//优先级低于栈顶
			{
				int numtop1 = numtop;
				numtop -= 1;
				int numtop2 = numtop;
				numtop -= 1;
				float temnum = cal(num[numtop2], num[numtop1], ch[chtop--]);
				num[++numtop] = temnum;
				if (chtop == -1)
					break;
			}
			ch[++chtop] = c;//入栈
		}
		else
		{
			ch[++chtop] = c;
		}
		return 0;
	}
	else if (c == '=')
		return 2;
	else
		return 0;
}

int main()
{
	char c;
	float ans = 0;
	int flagc = 0;
	while (c = getchar())//读取并入栈
	{
		flagc = ele(c, flagc);
		if (flagc == 2)
			break;
	}
	while (chtop != -1 && numtop != 0)//最后逐个出栈计算
	{
		int numtop1 = numtop;
		numtop -= 1;
		int numtop2 = numtop;
		numtop -= 1;
		ans = cal(num[numtop2], num[numtop1], ch[chtop--]);
		num[++numtop] = ans;
	}
	printf("%.2f", ans);
	return 0;
}