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新增:
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计算类（拥有计算功能）
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采用符号优先级计算方法
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对符号不匹配的如 -2 ，自动补为 0-2
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计算内核信息
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输入 -a 可以显示等式与结果
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输入 -p 可以显示计算逐步过程
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传入 -a 参数 且 传入 -p 参数
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传入 -a 参数 且 不传入 -p 参数
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规定并非万无一失，但暂未发现有悖原意的bug。
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如有发现bug，但求一知，万分感谢。
//
// main.cpp
// Calculator
//
// Created by admin on 16/2/25.
// Copyright © 2016年 YooRarely. All rights reserved.
//
#include <iostream>
#include <queue>
#include <stack>
#include <string>
#include <cmath>
#include <sstream>
using namespace std;
class Scan{
private:
bool err; // 输入是否出错
public:
// 字符是否为运算符
bool isOper(char c){
if ( c == '+' || c == '-' || c == '*' || c == '/' ) return true;
return false;
}
// 字符是否为数字
bool isCount(char c){
if (c>='0' && c<='9') return true;
return false;
}
queue <string> ToStringQueue(string input){
err=false;
queue <string > a;
int sum_kuohao = 0;
// 当输入未出错时遍历输入字符串
for (int i = 0; i < input.size() && ! err; i ++){
string s;
// 如果为 运算符 或 括号
if ( isOper( input[i] ) || input[i] == '(' || input[i] == ')' ) {
s = input[i];
if (!a.empty()){
string k=a.back();
if (input[i] == '(' && ( isCount( k[0] ) || k[0] == ')' ) ) err = true;
if ( isOper( k[0] ) && input[i] != '(' && input[i] != '-' ) err = true;
}
if (input[i] == '(') sum_kuohao ++;
if (input[i] == ')') sum_kuohao --;
if ( sum_kuohao < 0 ) err = true;
}// 否则 如果为数字
else if ( isCount( input[i] ) ){
bool dian=false;
while ( ! err && i < input.size() ){
if ( isCount( input[i] ) || input[i] == '.') s=s+input[i];
if ( input[i] == '.' ) {
if ( dian ) err = true;
dian = true;
}
if ( isOper( input[i+1] ) || input[i+1] == '(' || input[i+1] == ')') break;
i++;
}
if (dian && s[ s.size() - 1 ] == '.') err = true;
if ( s.size() > 10 ) err = true;
}
// 入队
a.push(s);
s="";
}
if ( sum_kuohao ) err = true;
if ( ! err && ! a.empty() ){
string k = a.front();
if ( isOper( k[0] ) && k[0] != '-' ) err = true;
k = a.back();
if ( isOper( k[0] ) ) err = true;
}
if ( err ) {
while ( ! a.empty() ) a.pop();
a.push("Error Input !");
}
return a;
}
};
class Print{
public:
void PrintStringQueue(queue<string> a){
while ( ! a.empty() ) {
cout << a.front() << endl;
a.pop();
}
}
};
class Calculate{
private:
bool print;
int tried (stack <char> &oper,stack <int> &important,stack <double> &count, int k){
while ( ! important.empty() && k <= important.top()){
double amazing = count.top();
count.pop();
switch (oper.top()) {
case '+':
if (print) cout<<count.top()<<"+"<<amazing;
count.top() += amazing;
if (print) cout<<"="<<count.top()<<endl;
break;
case '-':
if (print) cout<<count.top()<<"-"<<amazing;
count.top() -= amazing;
if (print) cout<<"="<<count.top()<<endl;
break;
case '*':
if (print) cout<<count.top()<<"*"<<amazing;
count.top() *= amazing;
if (print) cout<<"="<<count.top()<<endl;
break;
case '/':
if (amazing == 0) { return -1;}
if (print) cout<<count.top()<<"/"<<amazing;
count.top() /= amazing;
if (print) cout<<"="<<count.top()<<endl;
break;
}
oper.pop();
important.pop();
}
return 0;
}
public:
// 字符是否为运算符
bool isOper(char c){
if ( c == '+' || c == '-' || c == '*' || c == '/' ) return true;
return false;
}
// 字符是否为数字
bool isCount(char c){
if (c>='0' && c<='9') return true;
return false;
}
double getAns(queue<string> a,bool p){
stack <char> oper;
stack <int> important;
stack <double> count;
int k=0;
print=p;
while ( ! a.empty() ){
if (a.front()[0] == '(') k += 2;
if (a.front()[0] == ')') k -= 2;
if (isOper( a.front()[0] )){
if ( oper.size() == count.size() ){
count.push(0);
important.push(10000);
}
else if ( a.front()[0] == '*' || a.front()[0] == '/'){
if ( tried(oper, important, count, k+1) == -1 ) return 0.000000;
important.push(k+1);
}
else{
if ( tried(oper, important, count, k) == -1 ) return 0.000000;
important.push(k);
}
oper.push( a.front()[0] );
}
if (isCount( a.front()[0] )){
count.push( atof( a.front().c_str() ) );
}
a.pop();
}
if ( ! oper.empty() )
if ( tried(oper, important, count, -1) == -1 ) return 0.000000;
return count.top();
}
};
int main(int argc, const char * argv[]) {
string input;
bool p,a;
double ans;
int i;
Scan scan;
Print print;
Calculate Calculate;
p=false;
a=false;
i=1;
// getline(cin,input);
if (argc<2) return 0;
input=argv[i];
while (1){
if (input=="-a") {
input=argv[++i];
a=true;
continue;
}
if (input=="-p"){
input=argv[++i];
p=true;
continue;
}
break;
}
// print.PrintStringQueue( scan.ToStringQueue(input) );
ans=Calculate.getAns( scan.ToStringQueue(input) , p);
if (a) cout<<input<<"=";
cout<<ans<<endl;
return 0;
}