Question

I have the following code for finding the max value in a stack. It’s working but should I use another approach for finding the max value because after calling the getMax() function, I’m not able to display the stack a.

int Sorter:: getMax(){
    c.push(a.top());
    a.pop();
    while(!a.empty()){
            if(a.top() > c.top()){
            c.pop();
                    c.push(a.top());
                    a.pop();
            }
            else
                    a.pop();
    }
    return c.top();
}

Answer 1

Keep the maximum value in a side variable:

int max = a.top();
while(!a.empty()){
  c.push(a.top());
  a.pop()
  if(c.top() > max){
    max = c.top(); // find the maximum among the values of a.
  }
}

// This loop can be replaced with a.swap(c). As jogojapan mentioned.
// It is to demonstrate the principal.
while(!c.empty())
{
  a.push(c.top());  // return the values back into a
  c.pop();
}

return max;