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Programming Languages Suite
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Borland C++ V5.02
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STDLIB.PAK
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CALC.CPP
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C/C++ Source or Header
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1997-05-06
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/**************************************************************************
*
* calc.cpp - RPN Calculator -- Illustration of the use of stacks.
* Section 10.2.1
*
* $Id: calc.cpp,v 1.3 1995/08/29 19:00:41 oberg Exp $
*
* $$RW_INSERT_HEADER "slyrs.cpp"
*
**************************************************************************/
# include <vector>
# include <stack>
# include <iostream.h>
using namespace std;
//
// class calculatorEngine
// simulate the behavior of a simple integer calculator
//
class calculatorEngine {
public:
enum binaryOperator {plus, minus, times, divide};
int currentMemory ()
{ return data.top(); }
void pushOperand (int value)
{ data.push (value); }
void doOperator (binaryOperator);
protected:
stack< int, vector<int> > data;
};
void calculatorEngine::doOperator (binaryOperator theOp)
{
int right = data.top();
data.pop();
int left = data.top();
data.pop();
switch (theOp) {
case plus: data.push(left + right); break;
case minus: data.push(left - right); break;
case times: data.push(left * right); break;
case divide: data.push(left / right); break;
}
}
int main() {
cout << "Calculator example program, from Chapter 8" << endl;
cout << "Enter a legal RPN expression, end with p q (print and quit)" << endl;
int intval;
calculatorEngine calc;
char c;
while (cin >> c)
switch (c) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
cin.putback(c);
cin >> intval;
calc.pushOperand(intval);
break;
case '+':
calc.doOperator(calculatorEngine::plus);
break;
case '-':
calc.doOperator(calculatorEngine::minus);
break;
case '*':
calc.doOperator(calculatorEngine::times);
break;
case '/':
calc.doOperator(calculatorEngine::divide);
break;
case 'p':
cout << calc.currentMemory() << endl;
case 'q':
cout << "End calculator program" << endl;
return 0; // quit program
}
return 0;
}