C++ #include <iostream> #include <sstream> using namespace std; const int MAXSIZ

Question

C++

#include <iostream>
#include <sstream>
using namespace std;

const int MAXSIZE = 5;
class Stack {
   public:
      Stack();
      bool Empty();
      void Push(int item);
      void Pop();
      int Top();
      void displayStack();
   private:
      int stk[MAXSIZE];
      int top;
};
bool isNumber(string, int &);
int calculate(int, int, string);
int main() {
   Stack expStack;
   string inToken;
   int num, oprd1, oprd2, result;
   // *** enter your code here - ref to the steps
   // *** in the lab sheet.

   system("Pause");
   return 0;
}
Stack::Stack() {
   top = 0;
}
bool Stack::Empty() {
   if (top == 0)
      return true;
   else
      return false;
}
void Stack::Push(int item) {
    stk[top] = item;
    top++;
}                        
void Stack::Pop() {
   top--;
}                                  
int Stack::Top() {
   return stk[top];
}
void Stack::displayStack() {
   for (int i = 0; i < top; i++)
      cout << stk[i] << "   ";
   cout << endl << endl << top << endl;
}
/* this function will take a string and determine if it is
   an integer. The function will return true and store the
   integer value to number (a reference parameter). it will
   return false otherwise.
*/
bool isNumber(string inStr, int & number){
   stringstream ss;
   ss << inStr;
   number = 0;
   ss >> number;
   if (ss.good())
      return false;
   else if (number == 0 && inStr[0] != '0')
      return false;
   else
      return true;
}
/*
This function will use switch statement check the
first charactor in op to see if it is "=".
Then it will calculate and return the result. Assume
there are only 4 operators +, -, *, /
*/
int calculate(int num1, int num2, string op) {
   // *** write your code here
}

3 (20 points+20 Bonus points if correctly done) Given a Stack expStack Write code to evaluate any postfix expression provided by the user. please end the expression by an "sign. To simplify the code, we do not check for error expressions and assume user always type in To work on expression "2 5 + 4-9e illdo 1. Prompt user for enter the expression 2. Get one token from the expression (2, in this case), if there is one 3. if the token is an , break the loop if the token is an integer push the token into the stack print the number out else (the token must be one of the four operations +,-, '*, ) pop) twice and do the math on the operator push the result back to the stack 5. 6. loop back to line 2 pop the stack, the number should be the final result 12]

Explanation / Answer

#include #include using namespace std; const int MAXSIZE = 5; class Stack { public: Stack(); bool Empty(); void Push(int item); void Pop(); int Top(); void displayStack(); private: int stk[MAXSIZE]; int top; }; bool isNumber(string, int &); int calculate(int, int, string); int main() { Stack expStack; string inToken; int num, oprd1, oprd2, result; cout > inToken; if(inToken == "=") { break; } else if(isNumber(inToken, num)) { expStack.Push(num); } else { oprd1 = expStack.Top(); expStack.Pop(); oprd2 = expStack.Top(); expStack.Pop(); result = calculate(oprd1, oprd2, inToken); expStack.Push(result); } cout

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