Polish notation calculator on C++. @see https://en.wikipedia.org/wiki/Polish_notation

polish_calculator.cpp

#include <iostream>
#include <stdio.h>
using namespace std;

class cStack
{
private:
	int A[255];
	int ptr;
public:
	cStack(){
		ptr = 0;
	}
	void push(int & b){
		A[ptr] = b;
		ptr+=1;
	}
	int pop(){
		ptr-=1;
		return A[ptr];
	}
};

void add(cStack & tStack){
	int a, b, c;
	a = tStack.pop();
	b = tStack.pop();
	c = a + b;
	tStack.push(c);
}

void sub(cStack & tStack){
	int a, b, c;
	a = tStack.pop();
	b = tStack.pop();
	c = b - a;
	tStack.push(c);
}

void mul(cStack & tStack){
	int a, b, c;
	a = tStack.pop();
	b = tStack.pop();
	c = a * b;
	tStack.push(c);
}

int main()
{
	cStack stack;
	char c;
	char str[255]={0};
	int i=0;
	int temp;
	//cin>>noskipws;
	while(cin>>c) // Цикл пока считывание успешно
	{  
		str[i] = c;
		i+=1;
	}
	i=0;
	while(str[i]!=0)
	{
		if (str[i]=='+'){
			add(stack);
		}
		else if (str[i]=='-'){
			sub(stack);
		}
		else if (str[i]=='*'){
			mul(stack);
		}
		else {
			temp = (int)str[i] - 48;
			stack.push(temp);
		}
		i+=1;
	}
	cout << stack.pop();
return 0;
}