C_Language_PS&PC_Notes.ppt

C ~ Language
Introduction
The Language is a software which is used to communicate with the computer for
doing certain process. The language must have a compiler and do an operation.
Origin
 C – Language was created by Denise Ritchie and Brain Kernighan in Bell
Laboratories
 The Language available before the invention of C is B – Language, created by
Ken Thompson.
B leds to the development of C in 1970’s.
The ANSI(American National Standard Institute) C standard was finally
adopted in December 1989.
C is a middle level language, because it combines the best elements of high level
language with control and flexibility of assembly language. It is a case sensitive
language.

C ~ Structure
Documentation Section
Link Section
Definition Section
Global Declaration
return_type main(argumentlist)
{
variable declarations;
Statements;
}
Sub Function
Function 1
Function 2
:
:
Function n

Explanation
 Documentation Section – This is used to provide some
meaningful information about the program.
 Link Section - In this section we include the header files
whose functions are used in the program.
Eg : #include<stdio.h>
 Definition Section – In this section we use the Symbolic
Constants
Eg : # PI 3.14
 Global Declaration – In this section we declare the variable
which is going to used are accessed by any where in the
program.
 Main – This contains the coding (variable, statements)
which are going to be executed. Eg: printf().
 Function 1 … Function n – Sub functions which are used in
the programs.

Steps to do a Program.
Going to the C Editor.
 Click Start Run (Type) Command. Then the
command prompt will be appear. In that
 Type as follows
cd
cd tc
tc

In the Editor
 To create a new file.
Click File  New
 To save a file
Click File  Save(F2)
Type the file name with the extension as .c
Eg:
Test.c
 To open a file
Click File Open(F3)
 To Quit
Click File Quit
 To Compile file to see the errors
Click Compile Compile(Alt+F9)
 To run or execute a file to see the output
Click Run Run(ctrl+F9)

Escape Sequence
The escape sequence are used to format the
statements which are going to be displayed on the
screen. The most frequently used escape sequence
are:
 n – This is used to produce new line while
display
 t – This is used to produce tab while display.

Simple Program
/* Simple Program */ Document section
#include<stdio.h> Link Section
#include<conio.h>
void main()
{
clrscr();
printf("*");
printf("n Hai");
getch();
}

Comment Line
The Comment Line Symbols are used to make
the compiler not to execute. When a line is
declared as comments, It will not be executed by
Compiler. The types of Comments are :
 Single Line Comment – ( //… )
It used to make a single line as a comment
 Multi Line Comment – (/* … */)
It is used to make more than one line as a
comment

Variables & Constants
Variables
 These are the locations in the memory in which
the given values are stored.
 The values which can be changed during the
execution of the program.
Constants:
 The values which cannot be changed during the
execution of the program.

Data types
This will indicate the type of the value which is
going to be stored in the variable.
Data type Delimiter
====== ======
char %s,%c
int %d
long int %ld
float %f
double %lf
boolean --

Operators
These are used to do certain operations. The types
of operators are as follows.
 Arithmetic Operators:
These are used to do arithmetic operations. It consist
of two operands.
+ This is used to do addition operation.
- This is used to do subtraction operation.
* This is used to do Multiplication Operation.
/ This is used to do Division operation and return
“quotient” as result
% This is used to do division operation and return
“Remainder” as result.

 Relational Operators:
These are used to do the relational operation. It
can be the combination of two arithmetic
expression.
> Greater than
< Less than
>= Greater than or Equal to
<= Less than or Equal to
!= Not Equal to
 Logical Operators:
These are used to do the logical operation. It can
contain two relational expression.
& And
|| or
! not

Example Program
#include<stdio.h>
#include<conio.h>
void main()
{
int a,b,c;
clrscr();
a=5;
b=5;
c=a+b;
printf("C is : %d",c);
getch();
}

Control Statements
These are used to control the execution of the program.
Control Statements
Conditional Unconditional
Two Way Branching Multi Way Branching Go to
Simple … If
If … Else
If … Else If
Switch Case
 Conditional Control Statement:
Based on the given the execution of the program is controlled.
 Uncnditional Control Statement:
It is independent to control the execution. That means, it may or may
not dependent on the condition.

Simple If:
Syntax:
=======
if(Cond)
{
statement;
}
#include<stdio.h>
#include<conio.h>
void main()
{
int a;
clrscr();
printf("Enter the Value For A : ");
scanf("%d",&a);
if(a>=0)
{
printf("The Value is Accepted.");
}
getch();
}

If...Else
Syntax:
========
if(cond)
{
statement 1;
}
else
{
statement 2;
}

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b;
clrscr();
printf("Enter the Value for A : ");
scanf("%d",&a);
printf("Enter the value for B : ");
scanf("%d",&b);
if(a>b)
{
printf("A is Big.");
}
else
{
printf("B is Big.");
}
getch();
}

If … Else If
Syntax:
=======
if(Cond 1)
{
Statement 1;
}
else if(cond 2)
{
statement 2;
}
:
:
else if(cond n)
{
statement n;
}
else
{
else_Statement;
}

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b,c;
clrscr();
printf("Enter A,B,C : ");
scanf("%d%d%d",&a,&b,&c);
if(a>b && a>c)
{
printf("t%d is Big.",a);
}
else if(b>c)
{
printf("t%d is Big.",b);
}
else
{
printf("t%d is Big.",c);
}
getch();
}

Nested If
#include<stdio.h>
#include<conio.h>
main()
{
int a,b,c;
clrscr();
printf("Enter the A,B,C : ");
scanf("%d%d%d",&a,&b,&c);
if(a>b)
{
if(a>c)
{
printf("A is Big");
}
else
{
printf("C is Big");
}
}
else
{
if(b>c)
{
printf("B is Big");
}
else
{
printf("C is Big");
}
}
getch();
}

Switch Case
Syntax:
======
switch(exp)
{
case value_1:
Statement 1;
break;
case value_2:
Statemnt 2;
break;
case Value_3:
Statement 3;
break;
:
:
case value_n:
Statement n;
break;
default:
default statement;
break;
}

#include<stdio.h>
#include<conio.h>
void main()
{
int a;
clrscr();
printf("Enter the Value for A : ");
scanf("%d",&a);
switch(a)
{
case 1:
printf("One");
break;
case 2:
printf("Two");
break;
case 3:
printf("Three");
break;
default:
printf("The Value is not between 1 and 3.");
break;
}
getch();
}

Nested Case
#include<stdio.h>
#include<conio.h>
void main()
{
char c;
clrscr();
printf("Enter the Character : ");
scanf("%c",&c);
switch(c)
{
case 'a':
case 'e':
case 'i':
case 'o':
case 'u':
printf("The Vowel in Small Letter.");
break;
case 'A':
case 'E':
case 'I':
case 'O':
case 'U':
printf("The Vowel in Capital Letter.");
break;
default:
printf("Invalid Value.");
break;
}
getch();
}

Go to
Syntax:
=======
goto label
#include<stdio.h>
#include<conio.h>
main()
{
int i=0;
clrscr();
st:
i=i+1;
printf("i=%d",i);
if(i<10)
{
goto st;
}
getch();
}

Loop:
Set of Statements reapeted continously till the given condition is satisfied.
Types
=====
1)Entry Control Loop
2)Exit Control Loop
Entry Control Loop:
===================
In the entry control loop, the given condition is checked first, if the condition is true then only the
statements are executed.
Example:
========
1)For
2)while
Exit Control Loop:
==================
In the exit control loop, the statements are executed once, then the condition is verified.
Example:
========
Do...while

Unary Operators
 These operators are frequently in loops.
++ Increment operator:
eg : i++(i=i+1)
Pre Increment:
At first the value of variable is incremented and then the
action is carried out.
Post Increment:
At first the action is carried out then the value is
Incremented.
-- Increment operator:
eg : i--(i=i-1)
Pre Decrement
At first the value of variable is decremented and then the
action is carried out.
Post Decrement
At first the action is carried out then the value is
decremented.

For
 It is an entry control loop.
Syntax:
=====
for(initialization;test_condition;increment/decrement)
{
Statements;
}
Initialization:
In this part, we initialize the value for the variable.
Test_condition:
In this part, the condition until which the loop is to be executed.
Increment / decrement:
Here, the variable is incremented or decremented to reach the
condition

#include<stdio.h>
#include<conio.h>
void main()
{
int i;
clrscr();
for(i=0;i<5;i++)
{
printf("i=%d",i);
}
getch();
}

while
 It is an entry control loop
Syntax:
====
While(condition)
{
Statements;
}

#include<stdio.h>
#include<conio.h>
void main()
{
int i;
clrscr();
i=0;
while(i<5)
{
printf("i=%d",i);
i=i+1;
}
getch();
}

Do … While
 It is an exit control loop
Syntax:
====
do
{
Statements;
}
while(cond);

#include<stdio.h>
#include<conio.h>
void main()
{
int i=1;
clrscr();
do
{
printf("i=%d",i);
}
while(i<0);
getch();
}

Arrays
 Group of elements stored under a common
name.
Types:
=====
1)Single Dimensional Array
2)Double Dimensional Array

Single Dimensional Array:
Syntax:
======
datatype variable_Name[Size];
initialization:
===============
1) During Declaration
2)Using Assignment Operator
2) In Runtime Through Scanf using loop

During Declaration
 datatype variable_name[size]={value};
#include<stdio.h>
#include<conio.h>
main()
{
int a[5]={23,43,45,34,23};
char c[5]={‘a’,’e’,’i’,’o’,’u’};
clrscr();
printf(“The value in the cell a[2]=%d",a[2]);
Printf(“nThe Character in the cell c[2]=%c”,c[2]);
getch();
}

Using Assignment(=) Operator
variable_name[cell]=value;
#include<stdio.h>
#include<conio.h>
void main()
{
int a[3];
char c[3];
a[0]=1;
a[1]=2;
a[2]=3;
c[0]='a';
c[1]='b';
c[2]='c';
clrscr();
printf("The Value in the Cell a[2]=%d",a[2]);
printf("The Character in the cell a[2]=%c",a[2]);
getch();
}

In Runtime Through Scanf using loop
#include<stdio.h>
#include<conio.h>
main()
{
int a[5],i;
clrscr();
for(i=0;i<5;i++)
{
printf("nEnter the Value for Cell - %d :",i);
scanf("%d",&a[i]);
}
printf("nOutputn======");
for(i=0;i<5;i++)
{
printf("na[%d]=%d",i,a[i]);
}
printf("na[2]=%d",a[2]);
getch();
}

Practical Example
#include<stdio.h>
#include<conio.h>
main()
{
int reg[10],m1[10],m2[10],n;
int tot[10],i;
float avg[10];
clrscr();
printf("nEnter the No of Students:");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("nEnter the Reg.No of Student - %d : ",i+1);
scanf("%d",&reg[i]);
printf("Enter the Mark1 of Student - %d : ",i+1);
scanf("%d",&m1[i]);
printf("Enter the Mark2 of Student - %d : ",i+1);
scanf("%d",&m2[i]);
}
printf("nnOutputn======");
for(i=0;i<n;i++)
{
printf("nnReg.No of Student - %d is : %d",i+1,reg[i]);
printf("nMark 1 of Student - %d is : %d",i+1,m1[i]);
printf("nMark 2 of Student - %d is : %d",i+1,m2[i]);
tot[i]=m1[i]+m2[i];
avg[i]=tot[i]/2;
printf("nTotal of Student - %d is : %d",i+1,tot[i]);
printf("nAvverage of Student - %d is : %f",i+1,avg[i]);
}
getch();
}

Two Dimensional Array
 Syntax:
======
datatype variable_name[size][size];
#include<stdio.h>
#include<conio.h>
main()
{
int a[25][25],b[25][25],c[25][25];
int i,j,row,clm;
clrscr();
printf("ntttMatrix Addition");
printf("nttt====== ========");
printf("nEnter the Number of Rows & Columns : ");
scanf("%d %d",&row,&clm);
printf("nnEnter the Matrix-1 Values.n");

for(i=0;i<row;i++)
{
for(j=0;j<clm;j++)
{
printf("Enter the Value for the Cell a[%d][%d] : ",i,j);
scanf("%d",&a[i][j]);
}
}
printf("nnEnter the Matrix-2 Values.n");
for(i=0;i<row;i++)
{
for(j=0;j<clm;j++)
{
printf("Enter the Value for the Cell b[%d][%d] : ",i,j);
scanf("%d",&b[i][j]);
}
}
printf("nMatrix-1n");
for(i=0;i<row;i++)
{
for(j=0;j<clm;j++)
{
printf("t%dt",a[i][j]);
}
printf("n");
}

printf("nMatrix-2n");
for(i=0;i<row;i++)
{
for(j=0;j<clm;j++)
{
printf("t%dt",b[i][j]);
}
printf("n");
}
printf("nMatrix Addition isn");
for(i=0;i<row;i++)
{
for(j=0;j<clm;j++)
{
c[i][j]=a[i][j]+b[i][j];
printf("t%dt",c[i][j]);
}
printf("n");
}
getch();
}

Pointers
 It is a variable which is used to access the
address of other variable.
Syntax:
=====
Datatype *variable_name
Example:
=====
int *ptr;

#include<stdio.h>
#include<conio.h>
void main()
{
int *ptr,a;
clrscr();
printf("Enter value for a :");
scanf("%d",&a);
ptr=&a;
printf("nThe Value of ptr : %u",ptr);
printf("nThe Value of *ptr : %d",*ptr);
getch();
}

Character Pointer
#include<stdio.h>
#include<conio.h>
void main()
{
char nam[]={"hello"};
char *ptr={"hello"};
clrscr();
printf("nName = %s",nam);
printf("n*ptr =%s",*ptr);
getch();
}

Pointer as Array
#include<stdio.h>
#include<conio.h>
void main()
{
int a[5],*ptr[5],i;
clrscr();
for(i=0;i<5;i++)
{
printf("nEnter the Value for the cell a[%d] : ",i);
scanf("%d",&a[i]);
ptr[i]=&a[i];
}
printf("nOutputn======nn");
for(i=0;i<5;i++)
{
printf("nThe value of ptr : %u the value of *ptr : %d",ptr[i],*ptr[i]);
}
getch();
}

Functions
It is a sub program in which set of executable statements are stored
under a name.
Whenever the statements are needed, instead of repeating the statements
the 'name' is called. The name in which the set of statements are
stored is called "Function".
Calling Function:
======= =========
The function which calls another function is called "Calling function"
Called Function:
====== =========
The function which is called by another function is called "Called Function"
Arguments:
==========
These are the Values passed to the called function from calling function.
The arguments in calling function is called "Actual Argument". The argument
in called function is caled "Formal Argument".
Return Value:
======= =====
Values return by the called function to the calling function.

Types
 Without Argument Without Return Value
 Without Argument With Return Value
 With Argument Without Return Value
 With Argument With Return Value

Without Argument Without Return Value
#include<stdio.h>
#include<conio.h>
void func()//called function
{
printf("nControl is inside the function, ");
printf("Hai, I am function");
}
void main()
{
clrscr();
printf("nThe Control is going inside the function.");
func(); //calling function
prnitf("nThe Control Came out of the function and Enter
main.");
getch();
}

Without Argument With Return Value
#include<stdio.h>
#include<conio.h>
int func()//called function
{
int x, y;
int z;
printf("Enter the value for x : ");
scanf("%d",&x);
printf("Enter the value for Y : ");
scanf("%d".&y);
z=x+y;
return z;
}
void main()
{
int c;
clrscr();
c=func(); //calling function
prnitf("nThe result is : %d",c);
getch();
}

With Argument Without Return Value
#include<stdio.h>
#include<conio.h>
void func(int x,int y)//called function
{
int z;
z=x+y;
prnitf("nThe result is : %d",z);
}
void main()
{
int a,b,c;
clrscr();
printf("Enter the value for a : ");
scanf("%d",&a);
printf("Enter the value for b : ");
scanf("%d".&b);
c=func(a,b); //calling function
getch();
}

With Argument With Return Value
#include<stdio.h>
#include<conio.h>
int func(int x,int y)//called function
{
int z;
z=x+y;
return z;
}
void main()
{
int a,b,c;
clrscr();
printf("Enter the value for a : ");
scanf("%d",&a);
printf("Enter the value for b : ");
scanf("%d".&b);
c=func(a,b); //calling function
prnitf("nThe result is : %d",c);
getch();
}

Global Variable
It is a variable which is commonly used by all the functions.
#include<stdio.h>
#include<conio.h>
int g=10;
void func()//called function
{
printf("nThe Control is inside functionn");
printf("ng=%d",g);
}
void main()
{
printf("nThe Control is in side the main");
printf("ng=%d",g);
func();
g=g+10;
func();
getch();
}

Recursive Function
When a function calls itself then it is said to be recursive function.
#include<stdio.h>
#include<conio.h>
rec(int n)//Called function
{
if(n>=0)
{
printf(“nn=%d”,n);
rec(n-1);
}
else
return 0;
}
void main()
{
int a=5;
clrscr();
rec(a);//Calling function
getch();
}

String Functions
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
char s1[20],s2[20];
clrscr();
printf("Enter S1 : ");
scanf("%s",&s1);
printf("Enter S2 : ");
scanf("%s",&s2);
printf("strrev(s1) : %s",strrev(s1)); //To reverse a string
printf("nStrlen(s1) : %d",strlen(s1));//to find the length of the string
printf("nStrupr(s1) : %s",strupr(s1));//to convert the string to upper case
printf("nStrlwr(s1) : %s",strlwr(s1));//to convert the string to lower case
printf("nstrcmp(s1,s2) : %d",strcmp(s1,s2));//to compare the string s2 with s1
and retun the result
printf("nstrcpmi(s1,s2) : %d",strcmpi(s1,s2));//to compare the string s2 with s1
by not taking the case and retun
the result
printf("nstrcat(s1,s2) : %s",strcat(s1,s2));//to join the two strings
getch();
}

Structure
It is a collection of different items.
Syntax:
=======
struct structure_name
{
datatype 1 member 1;
datatype 2 member 2;
:
:
datatype n member n;
};
struct structure_name structure_variable;
structure_variable.member;

#include<stdio.h>
#include<conio.h>
struct stu
{
int rno;
char name[25];
int eng,tam,mat,sci,cs;
int tot;
float avg;
};
void main()
{
struct stu s;
clrscr();
printf("Enter the Rno :");
scanf("%d",&s.rno);
printf("Enter the Name : ");
scanf("%s",&s.name);
printf("Enter the English Mark : ");
scanf("%d",&s.eng);
printf("Enter the Tamil Mark : ");
scanf("%d",&s.tam);
printf("Enter the maths Mark : ");
scanf("%d",&s.mat);
printf("Enter the Science Mark : ");
scanf("%d",&s.sci);
printf("Enter the CS Mark :");
scanf("%d",&s.cs);

s.tot=s.eng+s.tam+s.mat+s.sci+s.cs;
s.avg=(float)s.tot/5;
clrscr();
printf("nRno is : %d",s.rno);
printf("nName is : %s",s.name);
printf("nEnglish : %d",s.eng);
printf("nTamil : %d",s.tam);
printf("nMaths : %d",s.mat);
printf("nSCience : %d",s.sci);
printf("nCS : %d",s.cs);
printf("nTotal : %d",s.tot);
printf("nAverage : %f",s.avg);
getch();
}

Structure as array
#include<stdio.h>
#include<conio.h>
struct stu
{
int rno;
char name[25];
int eng,tam,mat,sci,cs;
int tot;
float avg;
};
void main()
{
struct stu s[3];
int i;
clrscr();
for(i=0;i<2;i++)
{
printf("nnEnter the Details of Student - %dn",i+1)
printf("Enter the Rno :");
scanf("%d",&s[i].rno);
printf("Enter the Name : ");
scanf("%s",&s[i].name);
printf("Enter the English Mark : ");
scanf("%d",&s[i].eng);
printf("Enter the Tamil Mark : ");
scanf("%d",&s[i].tam);
printf("Enter the maths Mark : ");
scanf("%d",&s[i].mat);
printf("Enter the Science Mark : ");
scanf("%d",&s[i].sci);
printf("Enter the CS Mark :");
scanf("%d",&s[i].cs);
s[i].tot=s[i].eng+s[i].tam+s[i].mat+s[i].sci+s[i].cs;
s[i].avg=(float)s[i].tot/5;
}
clrscr();

for(i=0;i<3;i++)
{
printf("nnThe Details of student - %d",i+1)
printf("nRno is : %d",s[i].rno);
printf("nName is : %s",s[i].name);
printf("nEnglish : %d",s[i].eng);
printf("nTamil : %d",s[i].tam);
printf("nMaths : %d",s[i].mat);
printf("nSCience : %d",s[i].sci);
printf("nCS : %d",s[i].cs);
printf("nTotal : %d",s[i].tot);
printf("nAverage : %f",s[i].avg);
}
getch();
}

File Handlings
 File is a place where we can store the data
permanently
 There are many ways to handle a file, in that we
are going to see about
1) How to write the data to the file
2) How to read the data from the file

Writing to File
#include<stdio.h>
#include<conio.h>
void main()
{
char str;
FILE *fptr;
clrscr();
fptr=fopen("test1.txt","w");
printf("Enter The Text and Press ^ to stop.");
do
{
str=getchar();
putc(str,fptr);
}
while(str!='^');
getch();
}

Reading From File
#include<stdio.h>
#include<conio.h>
void main()
{
char str;
FILE *fptr;
clrscr();
fptr=fopen("arun.txt","r");
str=getc(fptr);
while(str!=EOF)
{
putchar(str);
str=getc(fptr);
}
getch();
}

C_Language_PS&PC_Notes.ppt

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C_Language_PS&PC_Notes.ppt