Data Structure and c

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# Data Structure and c - PowerPoint PPT Presentation

Data Structure and c. K.S.Prabhu Lecturer All Deaf Educational Technology. C Tokens. C Tokens. Keywords. It has 32 keywords. #include<stdio.h> #include<conio.h> void main() { char yn; clrscr(); do {. puts("enter y/n(yes/no)"); yn=getchar(); fflush(stdin); if(yn!='y'&&yn!='n')

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### Data Structure and c

K.S.Prabhu

Lecturer

All Deaf Educational Technology

Keywords
• It has 32 keywords.
#include

#include

void main()

{

char yn;

clrscr();

do

{

puts("enter y/n(yes/no)");

yn=getchar();

fflush(stdin);

if(yn!='y'&&yn!='n')

puts("invalid input");

}

while(yn!='y'&&yn!='n'); getch();

Constants
• A constant is an entity that doesn't change during the execution of a program.
• Followings are the different types of constants.
• Real constant
• Integer Constant
• Character Constant
• String Constant
1. Real Constant :
• It must have at least one digit.
• It must have a decimal point which may be positive or negative.
• Use of blank space and comma is not allowed between real constants.
• Example:
• +194.143, -416.41
Real Constant
• It must have at least one digit.
• It must have a decimal point which may be positive or negative.
• Use of blank space and comma is not allowed between real constants.
• Example:+194.143, -416.41
Integer Constant
• It must have at least one digit.
• It should not contain a decimal place.
• It can be positive or negative.
• Use of blank space and comma is not allowed between real constants.
• Example:
• 1990, 194, -394
Character Constant
• It is a single alphabet or a digit or a special symbol enclosed in a single quote.
• Maximum length of a character constant is 1.
• Example:'T', '9', '\$'
String Constant
• It is collection of characters enclosed in double quotes.
• It may contain letters, digits, special characters and blank space.
• Example:“I love Deaf“

“ All Deaf Educational Technology”

Identifier
• An identifier is used for any variable, function, data definition, etc.
• In the C programming language, an identifier is a combination of alphanumeric characters.
• An underline and the remaining being any letter of the alphabet, any numeric digit, or the underline.
String
• Strings in C are represented by arrays of characters.
• The end of the string is marked with a special character, the null character, which is simply the character with the value 0.
• The null character has no relation except in name to the null pointer.

char string[15] = "Hello world!";

Sample code Program

#include

#include

void main()

{

char in_str[21];

clrscr();

puts("Enter a string to a maximum of 20 characters");

getch();

}

output

Enter a string to a maximum of 20 characters

Youth

Variables
• It is date name used date value called by valuables.
• It is a data name which is used to store data and may change during program execution.
• It is opposite to constant.
Variable name is a name given to memory cells location of a computer where data is stored.

Syntax:

{data types}{Variables name}=[value]

Sample code Program

Example:

Int count index;

Float area price;

Chal class types;

Example of main program:-

Main

{

Int a,b,c,=10;

Char x;

Float num;

Local variables
• These variables only exist inside the specific function that creates them.
• They are unknown to other functions and to the main program.
• As such, they are normally implemented using a stack.
Example:
• {
• Int a, b, c, =10; local variable
• Char x;
• Float num;
• }
Global variables
• These variables can be accessed by any function comprising the program.
• They are implemented by associating memory locations with variable names.
Example:
• {Int a, b, c, =[10,20,30] ; Global variable
• Chal x;
• Float
• } (or)
• {Int a = [10]
• Int b = [20]
• Int c = [30]
• Chal [15]
• Float
• }
Example of Global Variable

Example:

{

Int a, b, c, =[10,20,30] ; Char x;

Float num;

}

{

Int a = [10];

Int b = [20];

Int c = [30];

Char[15];

Float num;

}

TYPEDEF STATEMENT
• typedef is a keyword in the C and C++ programming languages.
• The purpose of typedef is to assign alternative names to existing types.
• types declared with typedef end with ( '_t' )
• (e.g., size_t, time_t)

Syntax;-

• Typedef exp1, exp2,….., expn
All data types in between typedef and identifier can now be referred to by the identifier alone The statement.

typedef structtnode *Treeptr;

typedef structtnode

{

int count;

structtnode *left;

structtnode *right;

} Treenode;

Enumerated DataTypes
• The data type enum allows used identifier as value
• Syntax:
• Enum identifier {Element} Element 1, Element 2…..to Element n;
Example of main program
• Enum days {sun, mon, tue, wed, thu, fir, sat}
• Enum color{red, blue, orange, pink, green,}
• Enum holiday{Sunday, Saturday}
• Enum rainbow {red, blue, orange, yellow, green,}