#include <iostream>
#include <string>
using namespace std;


//Whenever this function is "called",
//the code inbetween the curly brackets
//is excecuted.
void sayHello()
{
	cout << "Hi 1370!" << endl;
	cout << "Is it fridya yet?" << endl;
}


//Can pass more than one parameter
void greetPersonToClass(string name, string course)
{
	cout << "Hello!" << endl;
	cout << "Welcome to " << course << " " << name << endl;
}

void greetPerson(string name)
{
	cout << "Hi " << name << ", welcome to the class" << endl;
}

//What parameters?
void annoyingKid(string phrase, int numTimes)
{
	for (int i = 0; i < numTimes; i = i + 1)
	{
		cout << "annoying kid says: " << phrase << endl;
	}
}

double squared(double x)
{
	double answer;
	answer = x * x;
	return answer;
}

//Return sum of num1 and num2
double add(double num1, double num2)
{
	return num1 + num2;
}

//Print values from start up to end
void printRange(int start, int end)
{
	for (int i=start; i<=end; i++)
	{
		cout << i << ", " << endl;
	}
	cout << endl;
}

double takeHomePay(int dollars, double tax)
{
	//How much tax is taken
	double taxDollars = dollars * tax;

	//subtract tax amount from dollars, return result
	double takehome = dollars - taxDollars;

	return takehome;
}


bool isGreater(double x, double y)
{
	if (x > y)
	{
		return true;
	}
	else
	{
		return false;
	}
}


//compute and return x^n (x raised to nth power)
//Run time:  how many steps does this take with respect to n
//Run time: O(n) 
double power(double x, int n)
{
	double product = 1;

	//loop n times (however you want)
	for (int i = 0; i < n; i++)
	{
		product = product * x;
	}

	//Ok, we've computed answer in variable product
	return product;
}

//Pass by reference example
void incrementByOne(int &number)
{
	number = number + 1;
}

int main()
{
	//Most basic of functions
	sayHello();

	//Passing a parameter to a function
	greetPerson("Lisa");
	greetPerson("Roger");
	greetPerson("Isabel");

	//Can pass multiple parameters
	greetPersonToClass("Lisa", "1370");
	greetPersonToClass("Simon", "1101");

	//Challenge #1:
	annoyingKid("Are we there yet?", 5); //print "are we there yet" 5 times
	annoyingKid("Any games on your phone?", 17);

	//Value returning functions
	int result;
	result = squared(5);
	cout << result << endl;

	cout << squared(8) << endl; //64
	cout << 5 + squared(3) << endl; //14
	squared(11); //What will happen? (you will see nothing)

	//Challenge #2:
	cout << add(3.14, 8.2) << endl; // 11.16

	//Challenge #3:
	printRange(5, 12); //5 6 7 8 9 10 11 12
	printRange(2, 5); //2 3 4 5

	//Challenge #4:
	//Write function that takes as in put your money earned
	//before taxes, as well as the tax rate,
	//and returns the takehome pay amount.
	cout << "I get to take home " << takeHomePay(500, .10) << " dollars." << endl;


	//Challenge #5:
	if (isGreater(3.14, 8))
	{
		cout << "Yep, 3.14 is bigger than 8" << endl;
	}
	else
	{
		cout << "Nope, 3.14 is NOT bigger than 8" << endl;
	}

	
	//Challenge #6: Ultimate challenge:
	cout << power(3, 4) << endl; //81
	cout << power(5, 3) << endl; //125
	

	//Challenge #7: Pass by reference!
	int x = 0;
	incrementByOne(x);
	cout << x << endl; // 1 
	incrementByOne(x);
	incrementByOne(x);

	cout << x << endl; // 3 

	return 0;
}