C PROGRAMING: A Beginner’s Course | CHAPTER 2 Data types, Constants, Variables, Keywords and I/O Statements

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CHAPTER 1   Introduction and structure of C program

CHAPTER 2   Data types,Constants, Variables and I/O Statements

CHAPTER 3   Operators and Expressions

CHAPTER 4   Control Statements

CHAPTER 5   Arrays

CHAPTER 6   String Manipulations

CHAPTER 7   Functions

CHAPTER 8   Structure,Unions and Enumerated Data types

CHAPTER 9   Pointers

CHAPTER 2

VARIABLE:

            variable is a name of the memory location. It is used to store data. Its value can be changed, and it can be reused many times. It is a way to represent memory location through symbol so that it can be easily identified.

            Variable declaration:

                        <data_type> variable1,variable2......;

            Ex:

                        int a;

                        float b;

                        char c;

                        char c[10];

                        double d;

KEYWORDS:

                Keywords are predefined, reserved words in C that are already defined by the c compilers. These are used to do functionality of C language. They are all having the special meanings

There are 32 keywords in C language,

auto

double

int

struct

break

else

long

switch

case

enum

register

typedef

char

extern

return

union

continue

for

signed

void

do

if

static

while

default

goto

sizeof

volatile

Const

float

short

unsigned

CONSTANTS:

Constants refer to fixed values that the program may not alter during its execution. These fixed values are also called literals. Constants can be of any of the basic data types like an integer constant, a floating constant, a character constant, or a string literal.

Ex:

                        int a=10;

                        float b=10.1;

                        char c=’a’;

                        char c[10]=”hello”;

DATA TYPES:

            Data types nothing but Keywords, which specifies, what type of data can be stored in the given location.

  1. Basic: int, char, float, double
  2. Derived: array, pointer, structure, union, enum
  3. User defined: typedef
  4. Void data type

Basic data types with its memory size and range according to the 32-bit architecture:

Data type

Memory size

Range

char

1 byte

(8 bits)

= -27  to  (27)-1

= −128 to 127

int

2 bytes

(16 bits)

= -215  to  (215)-1

= −32,768 to 32,767

float

4 bytes

(32 bits)

= -231  to  (231)-1

= -2,147,483,648 to 2,147,483,647

double

8 bytes

(64 bits)

-263  to  (263)-1

STANDARD INPUT FUNCTIONS:                                                                                                               

            1.scanf():

                        It is used to get input from user.

             syn:

                        scanf("control_string",&var1,&var2,......);

            ex:

                        scanf("%d",&a);

STANDARD OUTPUT FUNCTIONS:

            2.printf();

                        It is used to print values, messages.

            syn:

                        printf("control_string", var1,var2,.........);

            ex:

                        printf("%d",a);

 

CONTROL STRING OR FORMAT SPECIFIER:

            control string                         Data type

     1.          %d                                     int


     2.          %c                                     char

 

     3.          %s                                     char(string)

 

     4.         %f                                      float

 

     5.           %ld                                  double

 

EXAMPLE PROGRAMS:

1.     Write a program to display your name?

#include<stdio.h>

#include<conio.h>

void main()

{

char a='A';

char name[10];

clrscr();

printf("Enter the name:");

scanf("%s",name);

printf("This is what you have entered\n");

printf("%c\t%s",a,name);

getch();

}

2.     Write a program to add two numbers.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

a=10;

b=10;

c=a+b;

printf("The addition value is %d",c);

getch();

}

3.     Write a program to divide three numbers.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

float d;

clrscr();

printf("Enter any three values:");

scanf("%d%d%d",&a,&b,&c);

d=(a+b+c)/3.0;

printf("The average value of given three nos. is %f",d);

getch();

}

TN 10TH SAMACHEER MATHS EXERCISE 2.5 SOLUTIONS


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