13.6.cpp

这是C++的一部分练习程序!对初学者有一定的帮助作用。

#include "stack.h"
void calculator();
void main()
{
	calculator();
}
void calculator()
{
	stack <double> cal(100);
	char str[80];
	double a,b;
	cout<<"Tour function calculator.\n";
	cout<<"Enter 'q' to quit.\n";
	do {
		cout<<':';
		cin>>str;
		switch(*str)
		{
		  case '+': a=cal.pop();
			        b=cal.pop();
			        cout<<a+b<<endl;
			        cal.push(a+b);
			        break;
		  case '-': a=cal.pop();
			        b=cal.pop();
			        cout<<b-a<<endl;
			        cal.push(b-a);
			        break;
		  case '*': a=cal.pop();
			        b=cal.pop();
			        cout<<a*b<<endl;
			        cal.push(a*b);
			        break;
		  case '/': a=cal.pop();
			        b=cal.pop();
					if(!a)
					{
						cout<<"Divide by 0.\n";
						break;
					}
			        cout<<b/a<<endl;
			        cal.push(b/a);
			        break;
		  case '.': a=cal.pop();
			        cal.push(a);
			        cout<<"Current value on top of stack: ";
					cout<<a<<endl;
			        break;
          default:  cal.push(atof(str));
		}
	}while(*str!='q');
}