Lesson no : 2 - ( COUT function & Escape Sequence )

            Hello… People with Happy Faces.. Just right after finishing the Exams and having a Leisure time.. :)

            How you doing guys.. Having fun..!! I know.. Batch trips , Vacation etc,etc.. Well… me too.. :)

           We had to pause our C++ programming post series because I had semester exams for almost an entire month from 24th of May to 17th of June.. And You know what.. the exam was my B'day gift from KDU.. Yeah people.. It was on my Birthday.. 24th of May.. Yey.. Happy birth day for me..!! :)

           However I put some posts to discuss the model papers before the exam..

            So.. Now we have enough time to continue our amazing post series ;) Let’s start again..

             Last time we ended our post with explaining the cout in c++. 

Cout is use to display or print anything on console.

You can print 

• any text 
• any value of a variable 
• result of any operations with variables 

            Remember the last time, we printed your name and your address..?? This time lets discuss some techniques we can use to print text using cout. ( By print I meant displaying it on the console. Not actually printing it using a printer!!)

             When you print texts or words using cout, you can’t print some characters as output.

• “ - double quotes 
• ‘ – single quotes
• \ - backward slash
• ? – question marks

For example

Cout<<”Don’t come late. Did you miss the bus today? ”;

            If you try to print this you will probably end up in a error. Reason is that you have ? question mark and ‘ single quote to print.

            Now you have a problem , how to print “” or ? ‘ these.. Right..? Well, you have a way to do this. It is called "escape sequence" .

You can type any of those symbols right after a backward slash, then there will be no error.

Ex:-
cout<<” Don\’t come Late. Did you miss the bus today\? ”;

Cout<<” \”Here Im Using Double quotes with in double quotes.. ;)\” ”;



Here's a list of Escape Sequence.

Try this list in your code.

Specially this \t – tab and \b-backspace part.

Ok.. I will Stop this little post from here by leaving you some exercises. Please do these and I promise you to discuss them in my next post..



Ex 01: 

                **
               ****
              ******
             ********
            **********
           ************

Write a program to print above triangle.



Ex 02:

Try to print letters like this in the terminal.



P.S

     My Fellow readers. Thanks for staying with the blog. Now You can follow my blog by subscribing, using your email address. You can see it on top of the right side-bar. And please don’t be hesitate to ask any question about anything. See  you in my next post… Let's talk about variables in next post.. 
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Answers for the First Semester Exam

            Hey there.. Folks.. I'm Back after 1st sem exams.. Back in Action... ;) But, Still I can't take my mind out of the exams.. So I decided to do a post about  the exam paper.. Hope this will important to my blog readers.. :)

           This paper was included with 4 questions, and had to answer all of them. Lets start from the first one.

Q1.

a.) This is a theoretical question about programming. I copied       this answer-phrase from my previous post.

Types of Programming Errors. 

• Syntax Error
• This happens when we type incorrect codes, (ex: Missing Semi Colon ; , misspell a variable name, forget to close a Bracket  } ,  )These programs can not compile, it shows an error message.
• Logical Error.
• This error occur due to our misunderstanding of the programming logic,These programs compile without producing any error messages, but does something totally different other than what we expected from the program.(To get a total, instead of addition + we type multiplication * , this doesn't give any error message, but give an unwanted result.)  
• Runtime Error. 
• Programs with this error also compile without any error message until some error occur in runtime.
• Ex :- Devide by zero in runtime.

b.)

        (i)   Syntax Error

        (ii)  Logical Error

        (iii) Runtime Error

c.)

        (i) This statement is 'True' because in any program                      language the codes are executed line by line, so 

             without the declaration-part reads first, the program

             doesn't know what is the variable is.

        (ii) This is 'False' because, c++ is case sensitive. The                  variable name value with lower case letters and

             the variable name VALUE with upper case letters

             are not identical in c++, means both variables can be              exist at the same time.

        (iii) This is also 'True' because when 2 integers are                       divided there might be a remainder for that                             division. If any two of decimal numbers are divided

              (Floats) the answer is also a decimal point number,

              there won't be any remainder for that division.

d.)

            In this program there are 3 inputs, and we want to find the largest one only. so what we do is, we compare two numbers first and get the largest from those two and compare that with the other remaining number.(we need not to find the order of numbers , just the largest one only) To do that we need three selection conditions, one input and three output diagrams.

 Q2.

a.)

            In this question what you have to do is create some names for some variables they have given, using the rules and etiquette we have taught. 

(i)   float speed , float Speed , float spd ,.. etc.

(ii)  char Grade , char grade , char grades , char Grades ,              char Grad...etc

(iii)  float selPrice , float sel_price ,...etc

b.) 

(i)   int sum ; 

(ii)  count = 0 ;

(iii)  cout<<" The average is: "<<avg ;

       or

       cout<<"\" The average is: \" "<<avg ;

c.)

(i)  False- Even without the default case the switch works             without producing any error, but in most cases default is

      very essential part of the switch.

(ii)  False - Precedence of arithmetic operators are higher.

      Here's the order of precedence of operators.

(iii)  True- because || operator is the Logical OR operator.

d.)

Q3.

a.)

(i) while loop

    do while loop

     for loop

(ii) The while loop and the for loop are both entry-condition          loops. The test condition is checked before each iteration        of the loop, so it is possible for the statements in the loop        to never execute. 

     Exit-condition loop, in which the condition is checked after      each iteration of the loop, guaranteeing that statements          are executed at least once. This variety is called a do               while loop

(b)  

  (i)   2  1.5  1  0.5

  (ii)   10

          7

          4

          1

(iii)   10

(c)

Q4.

a.)

(i)   score

(ii)  double

(iii)  10

b.)

            A function has 2 main parts, Function Header and Function Body. As the features of a function we can consider few parts in detail, 

• return type ex:- int , static , void , float, double
• function name ex:-  int main ()  , double func1  ()
• parameter list ex:- int func1 (int num1, int num2)
• function body : rest of the function in curly braces

c.)

(i)   int   smallest   (int x,int y,int z)

(ii)  void  instructions  ()

(iii)  double  intToDouble  (int number)

d.)  

            In above function the parameters(arguments) in function header x and y are declared with ampersands. int &x , int &y.This is because we want to pass the value to the function by reference.

            That means when the values of the arguments are changed in the function, actual values of the reference variables are also changed. 

Here I attached the complete program for you to try.

#include <iostream>

using namespace std;

void zeroSmaller(int &x, int &y);

int main ()

{

   

   int a;

   int b;

 cout<<"Enter a value for  a"<<endl;

 cin>>a;

cout<<"Enter a value for  b"<<endl;

 cin>>b;

   zeroSmaller(a, b);

   cout << "After  value of a :" << a << endl;

   cout << "After  value of b :" << b << endl;

   return 0;

}

void zeroSmaller(int &x, int &y)

{

  if(x>y)

  {

      y=0;

  }

  else{x=0;}

   return;

}

            Here in function zeroSmaller, if x is lower then x will be set to zero by the function , but at the same time the actual value of a is also set to zero, because the value was passed by reference. And the value of b will be set to zero if the y is the lowest.

            So that's all for the first semester exam. Hang around with my c++ programming posts series to learn this completely from the beginning.  

            If you have anything to be more explained please mention in comments section below or any good or bad thoughts about this blog please comment.

See you in my next post.. Happy vacation.. :)

The first Program in C++. Using Code Blocks

Hello Again my Fellow Readers..!!

Hope you have installed Code Blocks and waiting to start your first C++ program and looking for me.. ;)

Sorry for the delay..! Let’s start quickly..

So if you opened a new project and opened it’s main.cpp file , now you can see the first program has already created…

Really..!!

Sure..  What you can actually see is bunch of lines of codes of a simple program. This line of code is known as the source code of your program. Means this is the set of instructions you gave to the program.

So what happened in this program.. Let’s check it out.. In the top tool bar you will see an icon with a cog wheel saying build.. You can build your program using it.. Click on it..

 (It will compile your program.. )  Then you see a green color arrow head icon next to build icon.. (Run) Click it and boom!! There is your first program.. It will open the command prompt and run your program in it.

This program will display the message “Hello World” in cmd. Press Enter and then the program will terminated.

            So what happened here was the source code was translated into machine code by a compiler. That’s what you done by building the program. Then you run the program.

So a compiler is a translator between programming language  and machine language.

There is another translator called interpreter. Both compiler and interpreter do the same thing but in different ways. A compiler translates the entire program at once. Interpreter does that by translating the codes line by line , consuming more time but, easier to identify errors more accurately than compilers.

Come back to your code, Select the code, and press delete. Right.. Now do exactly what I say..

1.     Type   #include<iostream>
     This is a header file, Also known as a preprocessor.

2.     Next line Type   include namespace std;
     This part is essential to output a message in cmd. Don’t forget the semi-colon ; at the end of the line.

3.     Then type   main()

4.     On the next line type   {
     Open curly brace.

5.     Then type   cout<<”Your Name”;
      replace the Your name with your name  ;) (Within quotation marks)  ex:-    “Shehan”. Don’t forget the semi colon again.

6.     Then type    return 0;

7.     And finally type       }

Done…   Now build and run the program.    

This will be the output.

Right, now I want you to delete   cout<<”Your name”;   and  type  cout<<”Your_Name”<<endl;  and  cout<<”Your_Address”<<endl; in two different lines.

Build it.. and run it.. And see the result.

       I think you got the idea that cout<<” ” is use to display an outputs in your program.   

       endl; - is refer as end of line, which creates a new line, after that.

       So…!   Use cout, to display different outputs.

 Try to use it creatively.

See You in m next Post..!!!   Have fun..    R.S.
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Let’s Start Coding ( Introducing Code Blocks )

Let’s Start Coding.

Hello Guys..!! Welcome to engineers favorite programming blog.. ;)

Last week we started our little chat about programming…  Computers, codes, Instructions so and so..

            And remember the simple game which I introduced to you.. I hope you have enjoyed your first approach to the world of programming.. :)

            Last week We came up to a point..

A computer program is a list of instructions that tells a computer what to do.. Everything a computer does is done by using  computer programs. A computer program is written in a programming language.”

Starting from that point,

            A program is a written thing, in a computer (list of instructions). To write something we need a language.

            OK..!!  We know some languages.. right..! we can use them to write a program.. (English or sinhala or tamil ) easy..!!

            But, unfortunately computers can-not understand human languages.
Computers, use very complicated language to operate which is really hard for us (human) to use. ( :D You know computers, they are geniuses) (ex : Machine Language -Binary)

            So in order to talk to a computer , and to make things done by him, we need an intermediate language. And create a program (List of instructions) using that language. Those kind of languages are known as programming languages.

 “FORTRAN” was the first programming language, created in 1953..

There are thousands of programming languages in the world.

·         Java.

·         PHP. ...

·         JavaScript. ...

·         Python. ...

·         Objective-C. ...

·         Ruby. ...

·         Perl. ...

·         C, C++ and C

So what you have to do is pick a language and learn to code using it.

            As our language, I Chose C++ to begin our journey..

C++ was a creation of Mr. Bjarne Stroustrup in 1979 from Bell Labs. See that bald guy here, that's him.

As the name stands for C++ is an enhancement to the C language 1983.

            We can make c++ programs by just using a compiler and note pad, Save the written program in “.cpp” extension and compile it and run it in command prompt. Or by using the terminal in Linux or Ubuntu You can do the same process..,

            But, That is a lot to do..

            To make the process easier, We can use an IDE (integrated development environment).

You might have heard about it already CODE BLOCKS. A Famous cross platform IDE. You can download it free from here http://www.codeblocks.org

Just download it, Run the setup and and you are ready to start programming.

            When you first opened the Code Blocks here's what you have to do,

1.    Open the Code Blocks.

2.    Select new Project.

3.    Select Console Program

4.    Select C++

5.    Give a name for Your Project.

6.    And Finish Wizard.

Then you will end up in this interface.

On the left side of the screen, there is a panel choose projects. And There will be your project in a tree view. Click on it (+ Sign).

Then You will see a file called main.cpp, Double click on it.

On the code screen a Sample program (Hello World) will appear, You can start program by changing it as you wish..  :) This is really Easy..!!

Try it now.. 

I will see you in my next post to tell you how to make your First C++ Program...!

CU...
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Let’s start at the very beginning.

When you think about the word “Programming” what comes to your mind.??..  A computer , Bunch of codes , a geeky thing which makes you  headache..

Yeah.. I know right.. ;)  But wait….!

What if I tell you that programming is not as hard as you think , or better what if it is the most easiest and fun thing to learn among your engineering subjects… ( You kidding me.. right..!!)  No…

Let me explain….

Think about your alarm clock for a minute.. At night you set your alarm (for a specific time you want) and go to bed, on next morning the alarm rings on time, you hear it , you snooze it and you sleep again… ;) right..

In that scenario you gave instructions to the alarm clock by setting the alarm and the clock worked according to your instructions..

The concept behind computer programming is same..  You give instructions to the computer and computer works according to those instructions and that set of instruction is called a computer program..

A software is a collection of such programs made by computer programmers.

So simply.. “A computer program is a list of instructions that tell a computer what to do.. Everything a computer does is done by using a computer program. A computer program is written in a programming language.”

Easy.. right..!! :) 

See.. That’s what I told you… I hope you’ve already started to feel it… You like it..? Follow me.. There is a lot to tell you.. 

See you in next post.. Bye..!

P.S

Hey there.. Here’s a bonus for you.. I’m hoping to tell you about variables, control structure, looping, arrays, functions in future…

  Those words might be new to you.. But eventually you will realize how easy those concepts are.. And I’m going to tell you an extra easier and fun way to understand those concepts..

This is a simple puzzle game called light-bot.

Lightbot is great fun and does a surprisingly thorough job of introducing some pretty complex principles of programming.

You don’t want any programming knowledge to play this game, But at the end of the game you will end up having a good understanding about all the basic concepts of programming. And you will receive a certificate like this

for completing a basic programming course .

Start it now..Play..!! https://lightbot.com/  https://lightbot.com/hour-of-code-2015.html

Hope you will enjoy.. See you soon.. Happy weekend..!! 
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