#include
	#include
	#include
	#include
	#include
	#include
	using namespace std;
	// test pattern: 1+2-3*4/5+6-7 => 12+34*5/-6+7- (postfix)
	int calc(char op, int num1, int num2) {
	int result;
	switch(op) {
	case '*': result = num1 * num2; break;
	case '/': result = num1 / num2; break;
	case '+': result = num1 + num2; break;
	case '-': result = num1 - num2; break;
	case '^': result = pow(num1, num2); break;
	}
	return result;
	}
	int main() {
	string postfix;
	cout
	getline( cin, postfix );
	deque postfixQueue;
	for( auto item:postfix )
	postfixQueue.push_back(item);
	stack stk;
	int num1, num2, result;
	while( !postfixQueue.empty() ) {
	char token = postfixQueue.front();
	if( isalnum(token) ) {
	stk.push( token - '0' );
	postfixQueue.pop_front();
	}
	else if( token == '+' || token == '-' ||
	token == '*' || token == '/' ) {
	postfixQueue.pop_front();
	num2 = stk.top(); stk.pop();
	num1 = stk.top(); stk.pop();
	result = calc( token, num1, num2 );
	stk.push(result);
	cout
	}
	}
	} I need help to 1. the user input 2. the calculation of following 4 operators: + - * / 3. tracing of all the content of the Operand Stack and Postfix Queue between changes.(I am missing this part)

Enter a postfix expression, q to quit: 12345+-+* Operand Stack Postfix Queue 2, 1 3, 2, 1 4, 3, 2, 1 5, 4, 3, 2, 1 3, 2, 1 9, 3, 2, 1 4+5 = 2, 1 -6, 2, 1 = 3-9 -4 1*-4 = Enter a postfix expression, q to quit: Enter a postfix expression, q to quit: 12345+-+* Operand Stack Postfix Queue 2, 1 3, 2, 1 4, 3, 2, 1 5, 4, 3, 2, 1 3, 2, 1 9, 3, 2, 1 4+5 = 2, 1 -6, 2, 1 = 3-9 -4 1*-4 = Enter a postfix expression, q to quit