a very basic c lecture

8/4/2019 A Very Basic c Lecture

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A VERY BASIC C LECTURE

Welcome to CODING CLUB


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WHAT WE WILL COVER

What is computer ?

What is computer architecture ?

What is HLL ?

What is compiler ?

What is C ?

What is C compiler ?

IDEs

What if I want more ?


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WHAT IS COMPUTER

A machine that can carry out set of

instructions

It understands only binary language.

But can it really understand ?

Answer - No.


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Computer can process binary stuff in the

sense that it has components that can

compare voltages and tell difference between

high and low voltage.

But COUNTER STRIKE is no binary

That is because we attach certain meanings to

the binary data.


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PROCESSING WHAT ON EARTH IS THAT ?

Running a given instruction to solve a specificpurpose.

What purpose ? And how ?

Say for instance . ADDITION.

4 = 100 in binary. ( 1x2^2 + 0x2^1 + 0x2^0)

5 = 101 in binary. ( 1x2^2 + 0x2^1 + 1x2^0)

Ask computer to solve 4+5


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COMPUTER ARCHITECTURE

THE BUILDING BLOCKS .


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The rules that we showed you make up the

computer architecture. At the core , every

computer is the same (except quantum

computers) , but how you combine those basicfunctions is what makes all the difference.


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So what architectures are available out there ?

INTEL x86 - eg. Pentium, Core2Duo .

INTEL x64 eg Pentium64 , i3 , i5 , i7

AMD x86 Turion , Athlon

AMD amd64 athlon64 , X3 etc .

Sun SPARC eg. ultraSPARC processors.

RISC processors .

And a host of others.

And binary for one architecture wont (usually) work on another

( In the sense that it isnt supposed to work. )


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HIGH LEVEL LANGUAGE

What is it ?A nomenclature where the machine code is namedsomething that makes direct sense to us. Likevariables , strings , integers , operators + , - etc.

Why do we need it ?

1. We cant program in binary.

2. We wont love to program in assembly.3. We have many other interesting things to do than

trying to add and subtract.


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WHAT IS A COMPILER ?

A program that converts a high level language intoits binary equivalent (given you provide thearchitecture) .

High level code (architecture independent)

A = b + c

ToAssembly (architecture dependent)

Add $r1 , $r2 , $r3

ToMachine code the executable (architecture dependent)

00100 000000000000 00001 00010 00011


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But wait !!!

Wasnt this supposed to be a C lecture ???

It was and it still is.

Just that you cannot feel C without this basicknowledge.


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WHAT IS C ???

A high level language that was developed in

late 1960s by DENNIS RITCHIE.

Has become very famous since then for its

simplicity and efficiency.

Has inspired many other languages directly or

indirectly . Like C++ , python , java.


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SYNTAX

Every statement ends with a semicolon.

int a , b ,c ;a = b + c ;printf( this is a string ) ;


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SYNTAX

Blocks of code are to be enclosed within curly

braces

if ( this_value > 100 )

{Statement1; // comments here

Statement2; //comments here

}


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OPERATORS

C supports all the real life operators . Like

+ , - , / , * , > , < ,= etc .Where each as the normal meaning.

It also has a few shortcuts like incrementing a variable .

a = a + 1; // new value of a = current value of a + 1

Can be written in short as

a++;


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LOOPING

The for loop . Iterates a code for given number oftimes.

int i;

for ( i = 0 ; i < 10 ; i++){printf(%d , i);

}

This code prints 0 1 2 3 4 5 5 7 8 9


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VARIABLES

Declaring variablesint a ; //an integer a

float x; //a fraction ie floating point variable x

float y; assigning variables values

a = 100;

x = 4.11;

y = x/a;// float divided by int is a float find out why.


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ARRAY OF VARIABLES

Declaration

int a[10]; // an array of size 10

//please note that this corresponds to

// index values 0 to 9.

Assigning values

a[4] = 10; //assign the fifth element of array value 10


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FUNCTIONS

Functions are blocks of code you can call from otherfunctions.

Like real life sine function can be represented as

float sine( float x)

{

// Procedure to calculate sine of xreturn // the value

}


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This is how it works ..

You call sine function and pass variable x to It as anargument. It uses this variable to calculate the function value

and returns you the result

Just like in real life you write

y = sine(x)

In C you can write

some_variable_y = sine( some_variable_x);


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LIBRARIES

These are commonly used codes that have beenwritten beforehand for your use.

Eg.

Library stdio.hprintf(some string);

scanf(%s , &some_character_array);

// please note that & before the character arrayname is must something you will understandwhen you delve deeper.


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COMPILATION

I am using the gcc compiler its pretty easy to

use in linux. Not so in windows.

You will definitely need an ide in windows.

I personally like CODEBLOCKS for C and C++

programming

There are others like DEV-C++ , VISUAL-C++

etc


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INTEGRATED DEVELOPMENT ENVIRONMENT


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WHERE DO I GO FOR MORE ???

First of all.

Wikipedia

Then refer some other top sites on google search

When you search C TUTORIALS

a very basic c lecture

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