Stock span problem

// C++ linear time solution for stock span problem 
#include <iostream> 
#include <stack> 
using namespace std; 

// A stack based efficient method to calculate 
// stock span values 
void calculateSpan(int price[], int n, int S[]) 
{ 
	// Create a stack and push index of first 
	// element to it 
	stack<int> st; 
	st.push(0); 

	// Span value of first element is always 1 
	S[0] = 1; 

	// Calculate span values for rest of the elements 
	for (int i = 1; i < n; i++) { 
		// Pop elements from stack while stack is not 
		// empty and top of stack is smaller than 
		// price[i] 
		while (!st.empty() && price[st.top()] <= price[i]) 
			st.pop(); 

		// If stack becomes empty, then price[i] is 
		// greater than all elements on left of it, 
		// i.e., price[0], price[1], ..price[i-1]. Else 
		// price[i] is greater than elements after 
		// top of stack 
		S[i] = (st.empty()) ? (i + 1) : (i - st.top()); 

		// Push this element to stack 
		st.push(i); 
	} 
} 

// A utility function to print elements of array 
void printArray(int arr[], int n) 
{ 
	for (int i = 0; i < n; i++) 
		cout << arr[i] << " "; 
} 

// Driver program to test above function 
int main() 
{ 
	int price[] = { 10, 4, 5, 90, 120, 80 }; 
	int n = sizeof(price) / sizeof(price[0]); 
	int S[n]; 

	// Fill the span values in array S[] 
	calculateSpan(price, n, S); 

	// print the calculated span values 
	printArray(S, n); 

	return 0; 
}