計算值許多值與許多算術運算符C++

Question

1. #ifndef CALC_H 
   #define CALC_H 
   
   
   class calc 
   { 
       double numb1; 
       double numb2; 
       public: 
        calc(); 
        void FUN_SUM(); 
        void FUN_Subtraction(); 
        void FUN_Multiplication(); 
        void FUN_Division(); 
        void FUN_Power(); 
        void FUN_Squareroot(); 
        void FUN_Switch(); 
        void FUN_Loob(); 
   
   }; 
   
   #endif // CALC_H 
   
   
   
   #include "calc.h" 
   #include <iostream> 
   #include <cmath> 
   using namespace std; 
   calc::calc() 
   { 
       numb1 = 0; 
       numb2 = 0; 
   } 
   void calc::FUN_SUM() 
   { 
       cout << "Enter number 1 " << endl; 
       cin >> numb1; 
       cout << "Enter number 2 " << endl; 
       cin >> numb2; 
       double Result_Of_Sum; 
       Result_Of_Sum = numb1+numb2; 
       cout << "The result of Sum = " << Result_Of_Sum << endl; 
   
   
   } 
   
   void calc::FUN_Subtraction() 
   { 
       cout << "Enter number 1 " << endl; 
   cin >> numb1; 
   cout << "Enter number 2 " << endl; 
   cin >> numb2; 
   double Result_Of_Subtraction; 
   Result_Of_Subtraction = numb1 - numb2; 
   cout << "The result of Subtraction = " << Result_Of_Subtraction << endl; 
   } 
   void calc::FUN_Multiplication() 
   { 
       cout << "Enter number 1 " << endl; 
       cin >> numb1; 
       cout << "Enter number 2 " << endl; 
       cin >> numb2; 
       double Result_Of_Multiplication; 
       Result_Of_Multiplication = numb1*numb2; 
       cout << "The result of Multiplication = " << Result_Of_Multiplication << endl; 
   
   } 
   
   void calc::FUN_Division() 
   { 
       cout << "Enter number 1 " << endl; 
       cin >> numb1; 
       cout << "Enter number 2 " << endl; 
       cin >> numb2; 
       double Result_Of_Division ; 
       Result_Of_Division = numb1/numb2; 
       cout << "The result of Division = " << Result_Of_Division << endl; 
   } 
   
   void calc::FUN_Power() 
   { 
       cout << "Enter number 1 " << endl; 
   cin >> numb1; 
   cout << "Enter number 2 " << endl; 
   cin >> numb2; 
   double Result_Of_Power; 
   Result_Of_Power = pow(numb1,numb2); 
   cout << "The result of Power = " << Result_Of_Power << endl; 
   } 
   
   void calc::FUN_Squareroot() 
   { 
       cout << "Enter the tow number you want Square root \n"; 
       cin >> numb1; 
   
       double Result_Of_Square_root; 
       Result_Of_Square_root = sqrt(numb1); 
       cout << "The result of Square root = " << Result_Of_Square_root << endl; 
   } 
   void calc::FUN_Switch() 
   { 
   int S; 
       cout << "Enter the number you operator do you want do it " << endl; 
       cout << "1- Addition" << endl; 
       cout << "2- Subtraction" << endl; 
       cout << "3- Multiplication" << endl; 
       cout << "4- Division" << endl; 
       cout << "5- Power" << endl; 
       cout << "6- Square Root" << endl; 
        cout << "7- Exit" << endl; 
       cin >> S; 
   
       switch (S) 
       { 
       case 1: 
   
        FUN_SUM(); 
        break; 
   
       case 2: 
   
        FUN_Subtraction(); 
        break; 
   
       case 3: 
   
        FUN_Multiplication(); 
        break; 
   
       case 4: 
   
        FUN_Division(); 
        break; 
   
       case 5: 
   
        FUN_Power(); 
        break; 
   
       case 6: 
   
        FUN_Squareroot(); 
        break; 
   
       default : 
        break; 
   
       } 
   } 
   
   void calc::FUN_Loob() 
   { 
       char L; 
   
       do 
       { 
   
        FUN_Switch(); 
   
   cout << "Do you want do another operator ('y' or 'n'?) \n"; 
        cin >> L; 
   if (L== 'y' || L=='Y' || L=='n' || L=='N') 
   
       continue; 
   else 
       cout << "you are enter roang later\n"; 
   
       } 
   
       while (L == 'Y' || L == 'y'); 
   
   } 
   
   
   #include <iostream> 
   #include "calc.h" 
   using namespace std; 
   
   int main() 
   { 
       cout << "Welcome to my simple Calculator\n"; 
   calc simple_calc; 
   
   simple_calc.FUN_Loob(); 
   cout << "\n Tank you for use my App :) :) " << endl; 
   
   return 0; 
   } 
   

我的問題是如何我可以使用戶計算值的任何值與像普通計算器運營

例如1 + 9 * 8-1 + 5我希望我的程序可以這樣做，但我不知道怎麼做？ :(:(

Answer 1

編寫計算器不是一件容易的事，因爲有更多的參與：

1. 運算符優先級
2. 分組
3. 表達式的評估

運算符優先級
運算符優先級是運算的分組，例如執行所有乘法加減之前的分割和分割。計算器程序應該處理沒有括號（分組）的優先級。

分組
更高級的計算器將允許使用圓括號對錶達式進行分組。計算器應該能夠評估最內在的表達並向外工作。

求表達式
這意味着允許多於1位的數字，和數字和符號之間的空格。此外，一旦表達式解析，它需要評估。計算器應根據操作（由用戶指定）調用適當的功能。

我建議你允許用戶輸入一個表達式，並且你的程序以字符串的形式讀取它。然後您的程序將解析字符串，然後評估表達式。

搜索網絡和StackOverflow的「C++計算器」的例子。