CSU 1655文本计算器

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Description

 Bob讨厌复杂的数学运算.看到练习册上的算术题,Bob很是头痛.为了完成作业,Bob想要你帮忙写一个文本版的四则运算计算器.这个计算器的功能需求十分简单,只要可以处理加减乘除和括号就可以了.你能够帮助Bob吗?

Input

每个样例一行,输入一个长度小于1500的包含有'(',')','+','-','*','/',和'1'~'9'组成的四则运算表达式.对于每个样例,参与运算数字在0~10000之间,表达式运算的结果在double的表示范围内.

Output

对于每一个例子,输出表达式的计算结果,精确到小数点后4位

Sample Input

3928*3180*3229+21372477*86381535+7452+3780+2061*280/3070/(7828-9348)

Sample Output

40333570297.000021396326.000012766.8763
栈
#include<cstdio>#include<cstring>#include<iostream>#include<queue>#include<vector>#include<map>#include<cmath>#include<stack>#include<algorithm>using namespace std;const int maxn = 100005;char s[maxn];int main(){while (scanf("%s", s) != EOF){stack<double> p;stack<char> d;for (int i = 0; s[i]; i++){if (s[i] >= '0'&&s[i] <= '9'){double u = 0;while (s[i] >= '0'&&s[i] <= '9') u = u * 10 + s[i++] - '0';p.push(u);i--;}else{if (d.empty() || s[i] == '(') d.push(s[i]);else{if (s[i] == ')'){while (d.top() != '('){double x = p.top();p.pop();double y = p.top(); p.pop();if (d.top() == '*') p.push(y * x);if (d.top() == '/') p.push(y / x);if (d.top() == '+') p.push(y + x);if (d.top() == '-') p.push(y - x);d.pop();}d.pop();}else{if (d.top() != '(')if (s[i] == '+' || s[i] == '-'){while (!d.empty() && d.top() != '('){double x = p.top();p.pop();double y = p.top(); p.pop();if (d.top() == '*') p.push(y * x);if (d.top() == '/') p.push(y / x);if (d.top() == '+') p.push(y + x);if (d.top() == '-') p.push(y - x);d.pop();}}else if (d.top() == '*' || d.top() == '/'){double x = p.top();p.pop();double y = p.top(); p.pop();if (d.top() == '*') p.push(y * x);if (d.top() == '/') p.push(y / x);if (d.top() == '+') p.push(y + x);if (d.top() == '-') p.push(y - x);d.pop();}d.push(s[i]);}}}}while (!d.empty()){double x = p.top();p.pop();double y = p.top(); p.pop();if (d.top() == '*') p.push(y * x);if (d.top() == '/') p.push(y / x);if (d.top() == '+') p.push(y + x);if (d.top() == '-') p.push(y - x);d.pop();}printf("%.4lf\n", p.top());}return 0;}

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