evaluating postfix expression using stacks

[scocuzza]

i feel like im really close to completing this but i cant seem to get the result printed out
i dont think im calling my evaluate function correctly and its not performing the operations..

#include <iostream>
#include <stack> //stack header file

using namespace std; 

typedef stack<int> stack_type;

char input(char&); 
void evaluate(stack_type&, char&); 

int main() 
{
	char op;
	stack_type operands;
	cout << "Enter how many numbers you want in your expression" << endl;
	input(op);
	evaluate(operands, op);

}
char input(char& op) 
{
	int x;
	stack_type operands;
	int numberAmount; 
	int count = 0;
	cin >> numberAmount;
	cout << "Enter "<< numberAmount << " numbers" << endl; 
	while (numberAmount > 0) {
	cin >> x;
	operands.push(x); 
	numberAmount--;
	count++;
	}
	count = count -1;
	cout << "Enter " << count <<" operators" << endl; 
	while(count > 0) {
	cin >> op;
	count--;
	}
	evaluate(operands, op); 
	return op;

}
void evaluate(stack_type& operands, char& op) 
{
	input(op); 
	while (operands.size() > 1)
    {
		int a = operands.top();
        operands.pop();

        int b = operands.top();
        operands.pop();


        int result;
	 switch (op)
        {
        case '+': result = a + b; break;
		case '*': result = a * b; break;
		case '/': result = a / b; break;
		case '%': result = a % b; break;
		case '-': result = a - b; break;
		default: 
			cout << "You have entered an incorrect operator";
        }
		 cout << result << endl; 
		 operands.push(result);
    }
   cout << operands.top() << endl; 
}

[scocuzza]

anyone?