buySellStock.cpp

// C++ Program to find best buying and selling days 
#include <bits/stdc++.h> 
using namespace std; 

// This function finds the buy sell 
// schedule for maximum profit 
void stockBuySell(int price[], int n) 
{ 
	// Prices must be given for at least two days 
	if (n == 1) 
		return; 

	// Traverse through given price array 
	int i = 0; 
	while (i < n - 1) { 

		// Find Local Minima 
		// Note that the limit is (n-2) as we are 
		// comparing present element to the next element 
		while ((i < n - 1) && (price[i + 1] <= price[i])) 
        
        	i++; 
		// If we reached the end, break 
		// as no further solution possible 
		if (i == n - 1) 
			break; 

		// Store the index of minima 
		int buy = i++; 

		// Find Local Maxima 
		// Note that the limit is (n-1) as we are 
		// comparing to previous element 
		while ((i < n) && (price[i] >= price[i - 1]))
        	i++; 
        
		// Store the index of maxima 
		int sell = i - 1; 

		cout << "\nBuy on day: " << buy 
			<< "\t Sell on day: " << sell << endl; 
	} 
} 

// Driver code 
int main() 
{ 
	// Stock prices on consecutive days 
	int price[] = { 2,3,4,2,1,2,3,2,4 }; 
	int n = sizeof(price) / sizeof(price[0]); 

	// Fucntion call 
	stockBuySell(price, n); 

	return 0; 
} 

// This is code is contributed by rathbhupendra