Learn Programming And Algorithms with C++

Written By San Saeteurn

What you Need to get Started:

Introduction

What is OOP, really:

	//All of your codes should contain a header like this.  It should include your name, the date created, date modified
	//CopyRight Stuff, and a Description of it's use.
	//Also, when you define a header file, always put in the following code:
	//#ifndef FILE_H
	//#define FILE_H
	//And at the End of the Header File, put #endif
	/***
	Created By: [Your Name Here]
	Date Created: [Put Date Here]
	Date Modified: [Put Date Here]
	CopyRight: [Whatever]
	Program Description Goes here
	***/
	#include <string>
	#include <iostream>
	using namespace std;//Because the original string.h and iostream.h has been set to standard,
			    //you must enter this line under it to show that it is standard (std)
	/***
	Class Greeting
	***/
	class Greeting//Class Definition (A Class is the Representation of an Object in C++)
	{
	    private://The Things under 'private' are not accessible by the outside
		string greet;//A Property of Class Greeting
	    public://The Things under 'public' are accessible by the outside	
		//This is a Function/Method
		void displayGreet()//Normally the Body of the Function will be in a separate file with
				   //extension .cpp and the this would be a header file w/ exten .h
		{
			//This Line tells the Operating System to Print the value of greet to the screen
		    cout << greet << endl;//The end of any Line need a semicolon ';'
		}
		//Notice that this function's name is the same as the Class's Name...hmmm
		Greeting();//This is a Special Function called the Class's Constructor.  This Function is
			   //automatically called when you instanciate a class
			   //It is Used to setUp the Class's property values
		{
		    greet = "Hello World";
		}
		//Notice what's weird about this Function
		~Greeting();//This Function is called the Class's Destructor Function.
			    //It is Automatically called when you destroy an instance of a class
			    //Often times, the comiler would generate a destructor
			    //function for you class if it is simple.  But don't count on it.
	};//At The end of all class definitions, you need a semicolom
	/***
	The Main Function
	***/
	int main()//The Main Function is where you use the classes to run a program
	{
	    Greeting gr;//An instanciation of The Previously defined class called 'Greeting'.  Gave it an identifier 'gr'
			//The Constructor is called when you enter this statment
	    gr.displayGreet();//Calling the Function 'displayGreet'
	    return 0;//Tells the CPU that the program ended without any problems.  The '0' mean no problems, a '1' means error occured.
	}//Notice you don't need a semicolon here, main is not a class, but a function.

class Greeting//Class Definition (A Class is the Representation of an Object in C++)

class Greeting

Before We Start Coding, you Must Understand the Following:

Identifiers:

Data Types:

Primitive Data Type:

Comments

Now Let's Look at the 4 Main Ideas of Programming:

Sequential

Branching

Looping

Methods/Function Calls

Sequential:

	int i;//Declare variable i
	i = 0;//set i to 0
	i = i + 1;//increment i by 1
	cout << i << endl;//print the value of i to the screen via standard output

Branching

	int i;//Instanciate an integer and call it 'i'
	cin >> i;//Prompt the User for an input value and store it in 'i'
	//the results of 'i == 0'is either true or false.  So we can actually assign this to a
	//Boolean value:  bool toZero = i == 0; is valid!
	if(i == 0)//Compare 'i' with the value 0.  If they are the same, execute the
		  //code inside the brackets, otherwise, skip it and go on.
	{
	    cout << "You Entered a 0!!" << endl;//Display the 'You Entered a 0!!' to the command line
	}

	int i;//declare i, automatically default as 0
	cin >> i;//Prompt user input and store it in i
	//Checks the value of i
	if(i == 0)
	{
	    cout << "You suck" << endl;//Do this if i is equal to 0
	}
	else if(i == 1)//Notice this one has no brackets!!!!!!!!!!
	    cout << "You are cool" << endl;//Do this if i is equal to 1
	else if(i == 2)
	{
	    cout << "What the...?" << endl;//Do this if i is equal to 2
	}
	else
	{
	    cout << "I am confused. :-(" << endl;//Do this if i is not 0, 1, or 2.  If i is something else!
	}

	if(boolean)
	{
	    ...code...
	}
	else//This part is optional
	{
	    ...More Code...
	}
	/**************************/
	//Is this LEGAL?????????
	if(boolean)//	#1
	{
	    if(boolean)//	#2
		if(boolean)//	#3
		    ...code...
		else//This goes with #3
		{
		    ...code...
		    //Is there an else for this if?
		    if(boolean)//	#4
		    {
			...code...
		    }
		}
	    //This else goes with if #2 not #4, why?
	    else if(boolean)//	#5
		...code...
	}
	else//What if does this else go with?
	    ...code...

	//Notice This
	if(boolean)
	    ...code...
	else if(boolean)
	    ...code...
	if(boolean)
	    ...code...
	else
	    if(boolean)
		...code...
	//Both of these mean the same thing.  White spaces are not inportant.
	if			(boolean)   {...code...}		else	if(boolean) {...code...}
	//This is a legal expression, but as you can also see, very hard to understand.  Not recomended, at ALL.
	//Please Don't DO THIS.
	//If fact, your entire program can be in ONE LINE!!!!!!

Looping:

	for(int i=0;i<10;i++)//Setting the initial value for the incrementor, the condition that must be met in order
			     //For the Loop to continue, and incrementing the loop counter.
	{
	    cout << "Hello World" << endl;//The statement that will be repeated a number of times.
	}

	while(boolean)//Loop goes if boolean is true, terminates when it is false.
	{
	    ...code...
	    ...some sort of incrementor that will eventually end the loop...//Otherwise the loop will never end, of wourse you have to
									   //set an initial value somewheer outside this loop
	}
	/**************/
	int i=0
	while(i < 10)//When i is greater than or equal to 10, exit the loop.
	{
	     cout << "Hello World" << endl;
	     i = i + 1;//This code is used very often, so the creators of C++ created a short way to represent this: i++;
		       //Notice this and the language name: C++.  That name was derived with that.
		       //C++ is 1 level higher than the original C, so C + 1 or C = C + 1 or C++!!!	:-)
	}

	for(initial value;boolean;incrementor)
	{
	    ...Code...//In this loop, the incrementor code is put at the location above that reads incrementor.
		      //The Condition is put in the field read boolean
		      //The initial value, well, if you don't get it by now, you don't have the brain power to be a programmer
	}
	/*****************/
	for(int i=0;i<10;i++)//All of these loops do the same thing, can you see what they do?
	{
	    cout << "Hello World" << endl;
	}

	for(int i=0;i<1000;i++)
	{
	    if(...Some Value... is not stupid)
		i = i + ...Some Value...
	    else
	    {
		break;//This statement forces the loop to exit.
	    }
	}

Methods/Function Calls: