File Processing

• Stream definition :

          A sequence of character. All input and  output data is a stream. C sees file as a stream.

• File Definition :

There are 2 types of  File

      • Text File

          - Saved in a text format or ASCII File

- Storage size depends on its data: 10000 needs 5 byte

- Can be open using standard text editor application

- Or c:>TYPE file_name

• Binary File 

storing numerical data in affixed format in line with micro-processor format definition

(example: format sign-magnitude 2’s complement).

–File is a collection of record

–Record is a collection of field

–Field is a block of byte

–Byte is collection of bit

• How to open a File ?

Opening a File using fopen():

  FILE *fopen (const char *filename, const char *mode );

fopen() defined at <stdio.h>

fopen() return a pointer to the start of a buffer area. Null will be returned if file unable to open.

Types of mode you can use

     Mode        Description

“r”       Opening a file to be read.

“w”      Creating a file to be written.

“a”       Opening a File for data append.

“r+”     Opening a File for read/write.

“w+”    Creating file for read/write.

“a+”     Opening a File for read/append

“rb”      Opening a File (binary) to be read.

“wb”     Creating a file (binary) for write operation.

Don't forget to close your opened file by using

int fclose (FILE *stream);

Structures, Union, and Memory Allocation

Structure Definition :

• Structure is a data type to store group of data with various of data type

• Structure component called member/field/element.

• Heterogeneous (various element data type)

• Structure in other programming language also called record

• Nested Structure is a structure with one of its element is another structure.

Structure Declaration :

Syntax

struct name_structure {

    dataType1 name_field1;

    dataType2 name_field2;

    …

};

Variable can be defined at declaration time

struct name_structure {

  dataType1 name_field1;

  dataType2 name_field2;

…

} name_variable_structure ;

Structure variable declaration

struct name_structure  name_variable_structure; 

Union Definition :

• Union is used for memory join. By using union, a memory location can be assigned for two or more variable with different data types

• Memory capacity used by union is the largest capacity used by any element of the union

Union Declaration :

Union Data Declaration

union name_union{

         typedata1   name_var1;

         typedata2   name_var2;

         ....

}   name_var_union;

Union Variable Declaration

union   name_union       name_var_union;

Memory Allocation Definition :

• Memory allocation:

  acquiring some memory space (RAM) managed by the OS to be used by a program.

• Memory de-allocation:

  releasing memory space (RAM) back to the OS.

Recursive, Function, and Cloud

Function Definition:

Function Structure

 return-value-type  function-name( parameter-list )

 {
   statements;

 }

return-value-type:  

data type of the value returned

•If not filled, then default data type will be used (default integer)

•If return-value-type is void then the function will not return value

Parameter-list: list of value sent from the function initiator (user)

Recursive Definition:

•Recursive is a function call inside a certain function calling itself

•Recursive Function is suitable for recursive problem

•Example :

 Factorial (n) or n! defined as follows :

 n! = 1, for n = 0;

 n! = n * (n-1)!, for n > 0

 4! = 4 * 3!

 3! = 3 * 2!

 2! = 2 * 1!

 1! =  1* 0!

 0! =  1

 Trace back : 4! = 1*2*3*4 = 24

Cloud Definition:

Cloud is an online-based storage used by user to store their data. There are 2 types of data

storage consist of offline-based storage and online-based storage. The examples of Cloud

storage company is iCloud, Microsoft OneDrive, Google Drive, and many more. In Cloud 

storage, there are Software as a Service (SaaS), Platform as a Service (PaaS), and

Infrastructure as a Service (IaaS).

Pointers and Arrays

Pointer

•Pointer is a variable that store the address of another variable

•Syntax :

  <type> *ptr_name;

•Two operators mostly used in pointer : * (content of) and & (address of)

Pointer to Pointer

•Pointer to pointer is a variable that saves another address of a pointer

•Syntax:

  <type> **ptr_ptr ;

Array

•Data saved in a certain structure to be accessed as a group or individually. Some variables

saved using the same name distinguish by their index.

•Syntax:

  type array_value [value_dim];

Array Initialization

•Array can be initialized explicitly without dimensional value declaration

Accessing Arrays

•Two analogous ways of accessing an element i=2;

  *(A+2) or A[2]

•A  is equivalent with &A[0] or a constant pointer to the first element of particular array

•To show A[2] on the monitor screen:

  printf(“%d”,A[2]) or

  printf(“%d\n”,*(A+2));

Pointer Constant & Pointer Variable

•Pointer variable is a pointer that can be assigned with new value at run-time.

•Pointer constant is a pointer that can not be assigned with new value at run-time

•Array is Pointer Constant to its first element of the array. Array can be filled with pointer variable.

One Dimensional Array

•Syntax 1D Array:

  type name_array[row];

Two Dimensional Array

•Syntax 2D Array:

type name_array[row][col];

Three Dimensional Array

•Syntax 3D Array :

type name_array[row][col][depth];

Array of Pointer

•An array filled with pointer/s

•Syntax :

type *array_name [value_dim];

Array of Character

•Array filled with character/s

•Syntax:

char array_name[value_dim];

String

•String is an array of character that ended with null character ( ‘\0’ or in ASCII = 0)

String Manipulation

•Types of function to manipulate string in string.h library

– strlen()

Return a value of string length; excluded null char

– strcpy(statement1, statement2)

Copy statement2 to statement1

– strncpy(statement1, statement2,n)

Copy first n characters of statement2 to statement1

– strcat(statement1, statement2)

Adding string statement2 to the end of string statement1

– strncat(statement1, statement2,n)

Adding n characters of string statement2 to the end of string statement1

– strcmp(statement1, statement2)

Comparing the value of string statement1 and statement2, if similar returning 0

– etc.

Repetition

Repetition

·One or more instruction repeated for certain amount 

of time

·Repetition/looping operation:

– For

– While

– Do-while

             1. For

•Syntax:

for(exp1; exp2; exp3) statement;

or:

for(exp1; exp2; exp3){

  statement1;

  statement2;

  …….

 }

exp1 :  initialization

exp2 :  conditional

exp3 :  increment or decrement

exp1, exp2 and exp3 are optional

EXAMPLE :

Program to print out numbers from 1 to 10

     #include<stdio.h>

int main()

{

    int x;

    for( x = 1 ;  x <= 10 ;  x++ ) printf( "%d\n", x );

    return(0);

}

      2. While

•Syntax :

while (exp) statements;

or:

while(exp){

  statement1;

  statement2;

   …..

}

EXAMPLE :

int counter = 1;

while ( counter <= 10 ) {

     printf( "%d\n", counter );

     ++counter;

}

3. Do-While

•Syntax :

do{

    < statements >;

} while(exp);

•Keep executing while exp is true

•exp evaluation done after executing the statement(s)

EXAMPLE :

int counter=0;

do {

     printf( "%d  ", counter );

  ++counter;

} while (counter <= 10);