// Lab 2 Lecture 

#include <iostream>
using namespace std;

int main()
{

// ------------------------------ Console I/O ---------------------------------

	// So far we have learned that we can print to the screen using cout
	// identifier (console out).

	cout << "print this to the console" << endl;

	// However, what if we want to take something from the user?
	// We can accomplish this by using the "cin" identifier (console in).
	// this will take a value from the user and put it inside a variable.

	// Note you must be careful to enter the correct data type.

	int usersNumber;

	cout << endl << "Enter a number" << endl;

	// take a number from the user
	cin >> usersNumber;

	// print the user's number back to the console
	cout << "You entered the number " << usersNumber << endl << endl;

	
// ---------------- Arithmetic Operators - + - * / % ++ -----------------------

	// Operator   Description
	// ----------------------
	//    +       addition
	//    -       subtraction
	//    *       multiplication
	//    /       division
	//    %       modulo


	// I am sure you are very familiar with each of the operators except
	// possibly the modulo operator (%), which gives the remainder of the
	// division of two values.

	// For example :

	int x = 11 % 3;

	cout << "11 % 3 = " << x << endl << endl;

	// x is 2 because 11 / 3 = 3r2

	// Example 2 : 8 % 5 = 3 because 8 / 5 = 1r3
	// Example 3 : 6 % 9 = 6 because 6 / 9 = 0r6
	// Example 4 : 0 % 4 = 0 because 0 / 4 = 0r0
	// Example 5 : 10042 % 10 = 2 because 10042 / 10 = 1004r2

	
// ----------------------- Compound Assignment Operators ----------------------

	// Are equivalent to assigning the result of an operation to the
	// first operand.

	// Operator     Expression     Equivalent To
	// -----------------------------------------
	//  +=           x += 5;       x = x + 5;
	//  -=           y -= x;       y = y - x;
	//  *=           z *= 7;       z = z * 7;
	//  /=           w *= y;       w = w * y;

	int y = 2;

	cout << "y = " << y << endl;

	y += 5;

	cout << "y += 5  =>  y = " << y << endl << endl;


// ----------------------- Increment and Decrement ----------------------------

	// Operator     Expression     Equivalent To
	// -----------------------------------------
	//   ++        x++; or ++x;      x = x + 1;
	//   --        x--; or --x;      x = x - 1;

	// As you can see, you are able to use this operator as a prefix and as a
	// suffix. In a simple expression, as seen above, they have exactly the
	// same outcome. However, when the operator is used as a prefix the value
	// is incremented or decremented before evaluating the containing
	// expression. Whereas, when the operator is a suffix the value is
	// incremented or decremented after the containing expression.

	// For example

	int p = 3;
	int s = 3;

	cout << "p = " << p << "     s = " << s << endl;

	cout << "++p is " << ++p << "  s++ is " << s++ << endl;

	cout << "p = " << p << "     s = " << s << endl << endl;
	
	// output: 
	// p = 3     s = 3
	// ++p is 4  s++ is 3
	// p = 4     s = 4
	
	// Example 2 
	p = 3;
	s = 3;
	int a;
	int b;
	
	a = ++p + 5; // add 1 to p before evaluating expression
	b = s++ + 5; // add 1 to p after evaluating expression

	cout << "a = " << a << ", b = " << b << ", p = " << p << ", s = " << s 
	     << endl << endl;
	// output : a = 9, b = 8, p = 4, s = 4

	
// ------------------------- Expression Evaluation ----------------------------

	// The compiler will follow the order of operations (PMDAS). Note that
	// C++ does not have a basic built in method of dealing with exponents.

	// Example:

	cout << "5 + 6 * 3 = " << (5 + 6 * 3) << endl;
	cout << "(5 + 6) * 3 = 	" << ((5 + 6) * 3) << endl << endl;


	// Integer division

	// when two integers are divided the result is the quotient with any
	// fractional part discarded (truncated). This is really important to
	// remember!

	// Example:
	cout << "Integer Division" << endl;
	cout << "4 / 3 = " << (4 / 3) << endl;
	cout << "3 / 4 = " << (3 / 4) << endl;
	cout << "12 / 5 = " << (12 / 5) << endl;

	// The division of two integer variables will also result in integer division

	int intA = 3;
	int intB = 4;

	cout << "intA / intB = " << (intA / intB) << endl;


	// However, if either the divisor or dividend is a floating point value 
	// then the result will be a floating point number.

	double doubleA = 3.0;

	cout << "4 / 3.0 = " << (4 / 3.0) << endl;
	cout << "intB / doubleA = " << (intB / doubleA) << endl << endl;
	

// ------------------------- Example 1 ----------------------------------------
	
	// Programs work sequentially from top to bottom. This is important to
	// make sure you do things in a logically correct order. The following
	// program will not work if any of the following steps are reordered.

	
	// declare variables
	float tempF;
	float tempC;

	// Take a value from the user and assign it to 'tempF'
	cout << "Please enter a temperature in fahrenheit:" << endl;
	cin >> tempF;

	
	// do math
	tempC = (tempF-32)*(5.0/9);

	// print result to screen
	cout << tempF <<"F = " << tempC << "C"<< endl << endl;

// ----------------------------------------------------------------------------
	
	return 0;
}