# include <iostream>
#include <string> // we will be using the string type

using namespace std;

#define PI 3.1416
int main(){
// some basic program, show compilation, syntax errors
	int n,m=10,t,u,v=100;
	cout << "I love learning C++ at 8AM in the morning\n"; 
//	return 0;
	
	
/*
	cout  << "Give me a number:";
	cin >> n;
	cout << "You gave me "<< n <<"\n"; // multiple streams out
//*/

//	return 0;


//	cin.ignore(2)	;
/* We learn declaration, initialization and assignment
   of variables and named literals of various datatypes */


// integer data types
	cout << "\n\nINTEGERS" << endl;
	short small_num; // variable declaration of type short
	unsigned short non_negative_small_num; // type unsigned short
	int whole_num = 13; // variable declaration and initialization of type int
	unsigned int non_negative_whole_num; // type unsigned int
	unsigned int another_non_negative_whole_num; // also type unsigned int
	long big_num; // type long
	unsigned long non_negative_big_num; // type unsigned long

// // assignments
	whole_num = 1969.134; // the last year that spirit was in Hotel California (thus said Eagles)
	small_num = 666.9;  // number of the beast (thus said Iron Maiden) :-)
	cout << "We haven't had that spirit here since " << whole_num << endl;
	cout << "Reckon the number of the beast: " << small_num << endl;
	cout << endl;

//	return 	0;
	
	cout << "PI =" << PI<<"\n\n";
	int myhex=0xF4; 
	cout<<"myhex="<<myhex<<"\n ... now in hex " << "myhex="<<hex<<myhex<<dec<<"\n\n";
	
//	return 0;
	int a=5;
	cout <<"SHIFTING a="<<a<<"\n";
	int ashift = a<<2; cout << "ashift=" << ashift << "\n"; 
	
//	return 	0;


// floating-point data types
	cout << "FLOATING POINT" << endl << endl;
	float frac_num; // type float
	double big_frac_num = 13.879; // type double
	long double very_big_frac_num; // type long double
	cout << "A fractional number is " << big_frac_num << endl;
	cout << endl;


//	return 0;
//////////////////////////////////////////////////////////////////////////////////


// // character and string datatypes
	cout << "Characters and strings" << endl << endl;
	char c ='Z';
	cout << "c="<< c <<" now make it an int... c="<<(int)c<<endl;
	
	char B='B';
	cout <<"transforming letter B to int..."<< (int)B <<"\n";
	
//	return 0;
	
	char letter = 'A'; // note the single quotes
	char same_letter = 65; // using the ASCII value of character 'A'
	string best_song = "Hotel California"; // note the double quotes
	cout << "Here is a letter: " << letter << endl;
	cout << "The same letter again: " << same_letter << endl;
	cout << "I love the song titled " << best_song << endl;
	cout << endl;

//	return 0;



// and the all-important cute boolean type
	cout << "Booleans" << endl << endl;
	bool flag = true;  // type bool
	bool same_flag = 1;  // true is 1, false is 0
	cout << "A boolean value: " << flag << endl;
	cout << "The same boolean value again: " << same_flag << endl;
	cout << endl;




// // don't forget the named constants
	cout << "Named constants" << endl;
	const double GAMMA = 0.577215; // that's Euler-Mascheroni constant
//	GAMMA =23.2; // note the keyword const and the initialization (must)
	cout << "Gamma is " << GAMMA << endl;
	cout << endl;


//	return 0;

// // let's get to know our operating system
	cout << "Size of various data types in our system" << endl << endl;
	cout << "Size of int data type is " << sizeof(int) << " bytes.\n"; // datatype as argument
	cout << "Size of long data type is " << sizeof(long) << " bytes.\n"; 
	cout << "Size of unsigned data type is " << sizeof(unsigned) << " bytes.\n";
	cout << "Size of short data type is " << sizeof(small_num) << " bytes.\n"; // variable as argument
	cout << "Size of unsigned data type is " << sizeof(unsigned) << " bytes.\n";
	cout << "Size of char data type is " << sizeof(char) << " bytes.\n";
	cout << "Size of float data type is " << sizeof(float) << " bytes.\n";
	cout << "Size of double data type is " << sizeof(double) << " bytes.\n";

	cout << endl;

//	return 0;

//integer division
	double frac = 5/2;
	cout <<"integer division frac=5/2="<<frac<<"   ...modulus=5%2="<<5%2<<"\n";
	frac=5.0/2;
	cout << "real division frac=5/2=" << frac <<"\n";


//	return 0;

//esape sequences
	cout <<"\n\nEscape characters\n lets try \\n twice:\n\nhere we are now... ";
	cout << "lets try \\r :\rXXX\n";
	cout <<" lets try \\b after 1234567:\bX\n";


//	return 0;

// we know how to swap two numbers!!!
	cout << "\n\n\nWe can swap two numbers, see ..."<< endl;
	non_negative_whole_num = 666;
	another_non_negative_whole_num = 13;
	cout << "one number = " << non_negative_whole_num << endl;
	cout << "another number = " << another_non_negative_whole_num << endl;
	unsigned temp = another_non_negative_whole_num;
	another_non_negative_whole_num = non_negative_whole_num;
	non_negative_whole_num = temp;
	cout << "And now ..." << endl;
	cout << "one number = " << non_negative_whole_num << endl;
	cout << "another number = " << another_non_negative_whole_num << endl;
	cout << endl;

	return 0;
}