Class FE Division: P

Unit 1 to Unit 3(As per revised Syllabus 2013-14)

Compiled by : Jayesh Bhangdiya

Let Us C Book and PPTs by Yashwant Kanetkar

Computer Fundamentals by Pradeep Sinha

Prof. Vishal Kaushal

Prof. Saurabh Khatri

To all other many references used.

Unit 1:

• Introduction to Programming

• Introduction to C

Unit 2:

• Flow of control

• Functions

Unit 3:

• Arrays

• Strings

Unit 4:

• Pointers

• Structures

Unit 5:

• Recursive Functions

• Sorting and Searching algorithms

“Let us C”, Y. Kanetkar, Second Edition, BPB Publication.

ISBN: 8176566217.

“Programming with C- Schaum‟s outline Series”, B.

Gottfried, Second edition, Tata McGraw Hill Publication,

ISBN 0-07-463491-7

“Programming language – ANSI C”, Brain W Kernighan

and Dennis Ritchie, Second edition ISBN 0-13-110370-9,

Directly sits on top of the hardware and controls it

Provides user with an interface or a virtual machine• More convenient to use than bare machine

Convenience + Resource managementMain functions

• Process mgmt• Memory mgmt• File mgmt• Security• Command interpretetion

Microsoft Disk Operating System

Single user OS for IBM and IBM

compatible PCs

Structured in 3 layers• BIOS

• Kernel

• Shell

Replaced by Windows OS

Developed in early 1970s at Bell Labs by Ken Thompson and Dennis Ritchie

Written in CMulti-user, time-sharing OSUsed on wide variety of computersStructured in three layers

• Kernel

• Shell

• Utilities

LINUX – similar, yet different

Machine Language Consists of combination of 0’s and 1’s that

represent high and low electrical voltage.

• Unsuitable for programming, difficult to

program.

• Machine dependent.

• Error prone.

• All programs are converted into machine

language before they can be executed.

Assembly Language• Similar to Machine level but replacing 0s and 1s

with Names and symbols

• Also known as Object code

• Uses symbolic codes to represent the machine operation code

• More readable

• Can be used to write instructions.

• Ex: ADD ------- 3E, etc

• Platform Dependent

• .obj extension

High-Level Languages

Programming languages that are easier

to learn.

Uses English like statements.• Readable familiar notations

• Availability of program libraries

• Platform Independent.

• Hides the details of computer.

• Example C language (.c extension)

High Level source

code(.c)

Middle level object

code(.obj)

Low level executable code(.exe)

Assemblers• Assemble to Machine

• Source Program to Object Program (one to one)

Compilers• High-level to Machine

• Source to Object (one to many)

• Separate compiler for each HLL on same comp

or same HLL on different computer

Linkers• Large programs span multiple source files

• Each source file can independently be translated into corresponding object files (modules)

• Linker combines them appropriately and creates a final executable

Loaders Interpreters

• One by one translates and executes the instruction with the input

Hybrid approachCompiler first compiles source code into

intermediate object code• Machine code for a “virtual” machine

• Based on standard IDL

Interpreter takes this object code and coverts it into and executes the machine code

Another variant – JIT compilation• Compiling the intermediate program

Plan of a computer program• Logic

• Step by step description of how to arrive at the

solution of a given problem

Algo representations• Program

• Flow chart

• Pseudo code

Also called Program Design Langauge (PDL)

Each and every instruction should be

precise and unambiguous

Each instruction should be able to be

executed in finite time

One or more instructions should not be

repeated infinitely• It should ultimately terminate

Desired results must be obtained after

termination

Pictorial representation of an algorithmUses standard symbols to represent

different meaningsActual instructions written within boxesBoxes are connected by arrowsFlowchartingMacro flowchart and micro flowchartAdvantages

• Better communication/documentation

• Efficient coding

• Systematic debugging and testing

Middle-level language• High level programming language with efficiency of assemble

language Developed in 1972 at AT&T‟s Bell Laboratories by

Dennis Ritchie and Brian Kernighan Standardized by ANSI and ISO Salient features

• User-defined data types

• Modular and structured programming concepts

• Rich library of functions

• Pointers and pointer operations

• Low-level memory and device access

• Small and concise

• Used for applications as well as systems programming

One or more modules called functionsCombination of statements between {

and }Null statement

• ; or {}

Simple statement is terminated by a semicolon

Compound statement or statement blockStandard library and header filesPreprocessor directives

Preprocessor is a program that prepares

a program for the compiler

Common directives• #include – import contents from another file

• #define - macros

• #ifdef…#else …#endif – for conditional

compilation

Name and type

Memory location

Can have 1 to 31 characters

Only alphabets, digits and underscore

allowed

Names are case sensitive

First character must be alphabet

Keywords are prohibited• 32 in number

Value never changesPrimitive constants

• Integer 8, +17, -6

Allowable range

• Real 8.6e5, +4.3E-8

Allowable range: -3.4e38 to 3.4e38

• Character „a‟, „%‟

LiteralNamed

C program

int count;

Short index;

C has no keywords for I/O operations

Standard library functions

\n, \t

Typically 10 zones of 8 columns each

“tab stops”

Less commonly used• \b, \f, \‟, \\, \r, \a, \”

Declared within the block and are local to the block

Lives as long as control is in that blockDefault storage class

• Includes formal argument declarationsMemory is allocated automatically upon

entry to a function and freed automatically upon exit from the function - stack

If explicitly initialized, it will be re-initialized each time

If not, the value will be garbage

Stored in register• Hence provide certain control over efficiency of the

program Variables which are used repeatedly or whose

access times are critical may be declared to be of storage class register

Variables can be declared as a register as follows

Everything else remains the same as auto Not guaranteed!

• Falls back to auto Not every type can be stored!

• falls back to auto

Static automatic variables continue to exist even after the block in which they are defined terminates. • Thus value is retained between function calls

Default initial value = 0Scope is local but life is as long as the

program lives Initializer is executed only onceDo not get created on stack, but in a

separate segment of memory called “data segment”

Scope: “global” Life: from point of definition through the remainder of

the program Defined outside of all functions

• Before or after, doesn‟t matter

• However, if you have to use before defining, then declare once more by using extern keyword

Variable defined in one file can be used in another by declaring as extern in the latter

• Best practice – include these in a header file and #include it Default initial value = 0 Static variable can also be declared outside all

functions• Treated as extern, but scope limited to that file only

Const - to explicitly insure that the value

is not changed, even accidentally

Volatile• Compiler may optimize by storing in register

• If you want new value to be loaded from memory

rather than register and stored back

• Especially used when values can be altered by

external entity

Short >= 2 bytes

Long >= 4 bytes

Short <= int <= long

These are used to make programs more

efficient

Short => short int

Long => long int

Free up the sign bit and almost double

the max value permitted • Explicitly call it “unsigned”

Default signed

Arithmetic

Logical• &&, ||, !

Relational• >, >=, <, <=, ==, !=

Order in which different operations are

performed

x+y*z

Order of evaluation when operators of

same precedence appear in an

expression

a=b=c=15

How to compile and execute programs

using command line in DOS

Use of vi and gcc in LINUX

Conversion of numbers in decimal, octal

and hexadecimal form

Control Statements / Branch Statements

IF-ELSE

Nested IF-ELSE

Conditional Expression

Switch statements

If (expression)• Statement1

Else• Statement2

Else is optionalDifference between only if and if-elseUse braces and indents to avoid mistakesScope of if and scope of elseNon zero means trueCoding shortcuts

• (expression) vs (expression != 0)• (!expression) vs (expression == 0)

Int I;

Printf (“Enter value of i “);

Scanf (“%d”, &i);

If (i==5);• Printf(“You entered 5\n”);

Return;

Who does the “else” belong to?

if (n>=0)• for (i=0; i<n; i++)

if (s[i]>0) {

printf(“something”);

return i;

}

else • printf( (“error: n is negative”);

Weather DetectorBetween 0 to 10

• Very cold!10 to 20

• cool20 to 30

• Pleasant

30 to 40• Hot

Three ways of implementing this!Please note, logical operators are short-

circuit

Multi-way decision if (expression)

• statement

else if (expression)• statement

...else

• statement

Last else is optional Improves efficiency – by skipping

evaluation

expression1 ? expression2 : expression3

Not only for arithmetic statements but for

others as well

Supports nesting

Watch out!• a>b?g=a:g=b;

It is an expression – can be used

wherever an expression can be used

Can you print – “You have x items”

Multi-way decision Only to match different constant integer values All case expressions must be different All subsequent statements are executed, until

break or return is encountered• Fall through – both boon and curse

What if there is no “default” “cases” and “default” can occur in any order Good practice – always put “break” after last

clause• Defensive programming

Switch may be nested

Multiple statements do not need to be in braces What happens when there is a statement without

“case”?• No error, but never gets executed

Disadvantage: you cannot have something like• Case i<=20:

Constant expressions can be used in case• Case 3+7: legal

• Case a+b: illegal

Switch is more efficient than equivalent if-else –especially when there are many cases

Loop statementsPre-test

• Condition is tested before each iteration

Post-test• Condition is tested after each iteration

FOR• Initializer

• Loop condition

• Incrementer

WHILE – has only loop conditionDO-WHILE

for (expr1; expr2; expr3)• statement

Scope of for is the immediate next statement All three are optional – but semicolons are

necessary for (i=0; i++<10;)

• printf(“%d\n”, i); Initialization, condition and increment can be any

expressions comma operator

• a pair of expressions separated by comma are evaluated left to right and the type and value of result is type and value of right operand

for (i=0; i<10; i++);• printf(“%d”, i);

while (expression)• statement

Same as saying – while (expression != 0)

For is usually preferred when

initialization and increment are single

statements and logically related

Unconditional branch GOTO label

• Transfer to statement marked with the label within the function

BREAK• Exit from innermost for, while, do or switch statements

• Control is transferred to statement immediately after the block in which break appears

CONTINUE• Skip to next iteration of for, while or do construct

• Control is transferred to statement beginning the block

RETURN

Label must be located in current functionContinue can appear only inside an

iteration statementBreak can appear only inside iteration or

switch statementAvoid goto

• Obscures flow of control

• Take the control to outer loop, deal with error condition

• Better to use more elegant ways

C program is a collection of one or more functions• Only one => main

A function have three things• Return type

• Name

• parameters

Prototype declaration Definition Call Any function can be called from any other function Function call sequence Function cannot be defined inside another function

A function can call itself• Recursion

Procedure Abstraction• Focus on “what” instead of “how”

Implementation Hiding

Modular Programs

Libraries

Function declaration

Parameter names are optional

Return type

Name

Number, type and order of arguments

return-type function-name (parameter decl) {• Declarations

• statements

}dummy(){}Can appear in any order in one source file or severalone function can‟t be split in mutliple

files

main( ){

printf ( ”\n I am in main” ) ;}

bombay( ){

printf ( ”\n I am in Bombay” ) ;}

kanpur( ){

printf ( ”\n I am in Kanpur” ) ;}

Output:I am in main

Functions

main( )

printf( )

scanf( )

getch( )

exit( )

gotorc( )

clrscr( )

for( )

while( )

if( )

switch( )

printf( )

scanf( )

exit( )

clrscr( )

kanpur( )

bombay( )

Std. Library User-Defined

Functions

main( ){

printf ( ”\n I am in main” ) ;

bombay( )

{

printf ( ”\n I am in Bombay” ) ;

}

kanpur( )

{

printf ( ”\n I am in Kanpur” ) ;

}

Output :

I am in main

I am in Bombay

I am in Kanpurbombay( ) ; kanpur( ) ;}

Function Call

Function Def.

A C program is nothing but a collectionof 1 or more functions

If C program contains 1 function its name

must be main( )

If C program contains more than 1 function

then one of them has to be main( )

Execution of any C program always begins

with main( )

Function names in a program must be unique

bombay( ){

printf ( ”\n I am in Bombay” ) ;}main( ){

printf ( ”I am in main” ) ;bombay( ) ;

}

Tip: Functions can be defined in any order

main( ){

printf ( ”\n I am in main” ) ;bombay( ) ;bombay( ) ;

}bombay( )

{printf ( ”\n I am in Bombay” ) ;

}

Tip: More the calls, slower the execution

kanpur( ){

printf ( ”\n I am in Kanpur” ) ; bombay( ) ;

}

main( ){

printf ( ”\n I am in main” ) ;

bombay( ) ; kanpur( ) ;

}

bombay( ){

printf ( ”\n I am in Bombay” ) ;

kanpur( ) ;} Tip: Any function can call

any other function

main( ){

printf ( ”\n I am in main” ) ;

main( ) ;

}

Local Call - Recursive Function

Process - Recursion

Two types of functions• Library functions

• User defined functions

Formals – Actuals

Parameters – Arguments

names need not be same

type, order and number must be the

same

main( )

{

int a = 10, b = 20, c = 30 ;

calsum ( ) ;

printf ( ”%d”, s ) ;

}

calsum( )

{

int a, b, c, s ;

}

int s ;

printf ( ”%d”, s ) ;

s = a + b + c ;

Garbage

Garbage

main( )

{

int a = 10, b = 20, c = 30 ; int s ;

calsum ( ) ;

printf ( ”%d”, s ) ;

}

calsum ( )

{

int s ;

}

printf ( ”%d”, s ) ;

s = x + y + z ;

a, b, c

int x, int y, int z

60

Garbage

Formal Arguments

ActualArguments

Void main( )

{

int a = 10, b = 20, c = 30, s ;

calsum ( a, b, c ) ;

}

Int calsum ( int x, int y, int z )

{

int ss ;

ss = x + y + z ;

return ( ss ) ;

}

s = calsum ( a, b, c ) ;

printf ( ”%d”, s ) ;60

return ( ss ) ;

return ( 60 ) ;

return ( x + y + z ) ;

Return control and value

return ; Returns only

control

calsum ( a, 25, d ) ;

calsum ( 10 + 2, 25 % 3, d ) ;

calsum ( a, calsum ( 25, 10, 4 ), d ) ;

d = calsum ( a, 25, d ) * calsum ( a, 25, d ) + 23 ;

calsum ( int x, int y, int z )

{

int ss ;

ss = x + y + z ;

return ( ss ) ;

}

Nested calls are legal.

Call within an expression are legal.

main( )

{

int a = 10, b = 20, c = 30 ;

printf ( ”%d%d”, s, p ) ;

}

sumprod ( )int x, int y, int z

ss = x + y + z ;

pp = x * y * z ;

sumprod ( a, b, c ) ; s, p = sumprod ( a, b, c ) ;

{

int ss, pp ;

return ( ss, pp ) ;

}

int s, p ;

A function can return only

1 value at a time

main( )

{

int a = 10, b = 20, c = 30 ;

int s, p ;

s = sumprod ( a, b, c ) ;

p = sumprod ( a, b, c ) ;

printf ( ”%d%d”, s, p ) ;

}

sumprod ( int x, int y, int z )

{

ss = x + y + z ;

pp = x * y * z ;

return ( ss ) ;

return ( pp ) ;

}

int ss, pp ;

60 60

Redundant

main( )

{

int a = 10, b = 20, c = 30 ;int s, p ;

s = sumprod ( a, b, c ) ;

p = sumprod ( a, b, c ) ;

printf ( ”%d%d”, s, p ) ;

}

, 1

, 2

sumprod ( int x, int y, int z, )

{

ss = x + y + z ; pp = x * y * z ;

int ss, pp ;

}

int code

if ( code == 1 )

return ( ss ) ;

else

return ( pp ) ;

Call by Value Original is not modified main() {

• int x = 3;

• func(x);

• printf(“%d”, x); } int func(int x) {

• x++;

• return x; } C‟s calling convention is right to left

• int a = 1;

• printf(“%d %d %d\n”, a, ++a, a++);

• 3 3 1 !!

Return is optionalAny number of return statements are

allowedReturn need not be the last statement return expression; return;

• return value is garbage return (2);Function need not return a valueCaller may ignore return valueOnly one value at a time can be returnedCompiler only gives warnings

Returning a non-integer value

Call by value / Call by reference

Recursion

square ( 2.0 ) ;

main( )

{

a = square ( 2.0 ) ;

b = square ( 2.5 ) ;

c = square ( 1.5 ) ;

printf ( ” %f %f %f ”, a, b, c, ) ;

}

square ( )float x

{

float y ;

y = x * x ;

printf ( ” %f ”, y ) ;

return ( y ) ;

}

FunctionPrototype

4.0 6.0 2.0

float a, b, c ; float square ( float ) ;

4.0

6.25

2.25

float square ( float x )

scope is local to the function

x defined in main() is not available in

func() and vice versa

Local

Global

Topics

Scope of variable

Automatic variables

External variables

Scopes and longevity of above types of

variables.

10

2

1. Scope: the scope of a variable determines

over what part(s) of the program a

variable is actually available for

use(active).

2. Local(internal) variables: are those which

are declared within a particular function.

3. Global(external) variables: are those

which are declared outside any function.

10

3

Are declare inside a function in which they are to be utilized.

Are declared using a keyword auto.eg. auto int number;

Are created when the function is called and destroyed automatically.

This variable are therefore private(local) to the function in which they are declared.

Variables declared inside a function without storage class specification is, by default, an automatic variable.

If automatic variables are not initialized they will contain garbage.

10

4

int main(){ int m=1000;function2();printf(“%d\n”,m);

}function1(){int m = 10;printf(“%d\n”,m);

}function2(){ int m = 100;

function1();printf(“%d\n”,m);

}

10

5

Output

10

100

1000

These variables are declared outside any function.

These variables are active and alive throughout the entire program.

Also known as global variables and default value is zero.

Unlike local variables they are accessed by any function in the program.

In case local variable and global variable have the same name, the local variable will have precedence over the global one.

Sometimes the keyword extern used to declare these variable.

10

6

int number;float length=7.5;main(){ number = 19; length=7.5;

}funtion1(){number = 19; length=7.5;

}funtion1(){number = 19; length=7.5;

}

10

7

int count;

main()

{count=10;

. . .

. . .

}

funtion()

{int count=0;

. . .

. . .

count=count+1;

}

The variable number and

length are available for use in

all three function

When the function references the

variable count, it will be referencing

only its local variable, not the global

one.

int x;int main(){x=10;printf(“x=%d\n”,x);printf(“x=%d\n”,fun1());printf(“x=%d\n”,fun2());printf(“x=%d\n”,fun3());}int fun1(){ x=x+10;return(x);

}int fun2(){ int xx=1;return(x);

}

10

8

int fun3(){ x=x+10;return(x);

}

Once a variable has been declared

global any function can use it and

change its value. The subsequent

functions can then reference only

that new value.

Output

x=10

x=20

x=1

x=30

int main(){

y=5;. . .. . .

}int y;

func1(){y=y+1}

10

9

• As far as main is concerned, y is not

defined. So compiler will issue an error

message.

• There are two way out at this point

1. Define y before main.

2. Declare y with the storage class extern

in main before using it.

int main(){extern int y;. . .. . .

}func1(){extern int y;. . .. . .}int y;

11

0

Note that extern declaration

does not allocate storage

space for variables

11

1

11

2

11

3

11

4

#include <stdio.h>

int add_numbers( void ); /* ANSI function prototype */

main()

{

auto int result;

int value1, value2, value3;

value1 = 10;

value2 = 20;

value3 = 30;

result = add_numbers();

printf("The sum of %d + %d + %d is %d\n",

value1, value2, value3, result);

}

int add_numbers( void )

{

auto int result;

int value1, value2, value3;

result = value1 + value2 + value3;

return result;

}

11

5

Static Variables and constants in C

main( ){

printf ( ”Enter Marks” ) ;

scanf ( ”%d %d %d”, &m1, &m2, &m3 ) ;per = ( m1 + m2 + m3 ) / 3 ;printf ( ”%d”, per ) ;

}

int m1, m2, m3, per ;

for ( i = 1 ; i <= 10 ; i++ ){

}

int i ;

printf ( ”%d”, per ) ;

Use 10 variables each holding 1 value

Use 1 variable holding all 10 values

Array

What is an Array?

Array is a variable capable of

holding more than 1 value at a time

32, 62, 65, 42, 48, 70, 80, 86, 92, 68{ }per =

peri per perii

per ( i ) per [ i ]

Screen

per3per1 per6

per10

main( ){

printf ( ”Enter Marks” ) ;

scanf ( ”%d %d %d”, &m1, &m2, &m3 ) ;per[ i ] = ( m1 + m2 + m3 ) / 3 ;

}

int m1, m2, m3, per[ 10 ] ;

for ( i = 1 ; i <= 10 ; i++ ){

}

int i ;

printf ( ”%d”, per[ i ] ) ;

for ( i = 1 ; i <= 10 ; i++ )

0 9

0 9

Array?A

Screen

0

0

int i = 2 ;main( ){

int a[ ] = { 7, 6, 11, -2, 26 } ;

optional

int b[ 10 ] ; compulsory

int c[ ] = { 16, 13, -8, -7, 25 } ;10

printf ( ”%d%d”, sizeof ( a ), sizeof ( b ) ) ;

printf ( ”%d%d”, a[ 0 ], b[ 0 ] ) ;

scanf ( ”%d%d%d”, ) ;&c[ 7 ], &c[ 8 ], &c[ 9 ]

c[ 5 ] = 3 + 7 % 2 ;

c[ 6 ] = c[ 1 ] + c[ 3 ] / 16 ;

}

10 20

int i ;i = 2 ;

7 G

Arrays can be initialized

Array elements can be scanned

Array elements can be calculated

Arithmetic on array elements is allowed

Then how are they different?

main( ){

int i = 3, j = 20, k = -5, l = 7, m = 11 ;

int a[ ] = { 3, 20, -5, 7, 11 } ; int ii ;

printf ( ”%u %u %u %u %u”, &i, &j, &k, &l, &m ) ;

for ( ii = 0 ; ii <= 4 ; ii++ )

printf ( ”%u”, &a[ ii ] ) ;

502 504 506 508 510

3 20 -5 7 11

502 504 506 508 510

a[0] a[1] a[2] a[3] a[4]

100 }

400 500 700 600

3

i

100

20

j

400

k

-5500

7

l

700

11

m

600

a[ ] = { 2, 1.4, ’A’, 6 } ;

- Adjacency

- Similarity

int

main( ){

int a[ ] = { 3, 60, -5, 7, 11 } ;int i ;

for ( i = 0 ; i <= 4 ; i++ )

printf ( ”%d”, a [ i ] ) ;

}

a[ i ] = a[ i ] * 2 ;

for ( i = 0 ; i <= 4 ; i++ )

0

0

Subscript outof range

3 60 -5 7 11500 502 504 506 508

a[0] a[1] a[2] a[3] a[4] a[5] a[6]

510 512

Arrays are variables capable of storingmultiple values

Array elements are stored in adjacentmemory locations

Checking the bounds of an array is programmer’s responsibility

main( ){

int a[ ] = { 7, 9, 16, -2, 8 } ;

int i ;

display ( a[ 0 ], a[ 1 ], a[ 2 ], a[ 3 ], a[ 4 ] ) ;

for ( i = 0 ; i <= 4 ; i++ )

display1 ( a[ i ] ) ;

}

display ( ){

printf ( ”%d %d %d %d %d”, i, j, k, l, m ) ;

}

display1 (int n) {

printf ( ”%d”, n ) ;

}

int i, int j, int k, int l, int m

Passing Array Elements to Functions

Whichis good?

printf ( ”%d”, a[ ][ ] ) ;

main( ){

int a[ ][ ] = {

{ 2, 6, 1, 8, 4 }

{ 1, 2, 5, 6, 8 }

{ 7, 9, 8, 7, 21 }

{ 4, 5, 6, 8, 10 }

} ;

int i, j ;

2 4

printf ( ”%d %d”, sizeof ( a ), a ) ;

for ( i = 0 ; i <= 3 ; i++ )

{

for ( j = 0 ; j <= 4 ; j++ )

printf ( ”%d”, a [ i ][ j ] ) ;

printf ( ”\n” ) ;}

}

5

int b[ ][1][2][3]

optional

compulsory

21

40 4080

optional

,

,

,

compulsory

compulsory

optional

Exception

int a[ ][ 4 ] = {7, 2, 6, 1, 9, 3, 4, 5, 10, 12, 16, 18

} ; }

Row Major

502 504 506 508 510 512 514 516 518 520 522 524

main( ){

9 3 4 5 10 12 16 181627

Representation of 2-D Arrays in Memory

main( ){ int a[ ][ ] = {

7, 2, 6, 13, 5, 4, 86, 2, 9, 50 1, 2, 3, 8

} ;

,,,

big = a[ 0 ][ 0 ] ;

for ( i = 0 ; i <= 3 ; i++ )

for ( j = 0 ; j <= 3 ; j++ ){

{if ( a[ i ][ j ] > big )

big = a[ i ][ j ] ;{

r = i ; c = j ;}

}}

printf ( ”%d ”, big ) ; printf ( ”%d %d ”, r, c ) ; }

4

r = 0 ; c = 0 ;

int i, j, big ; int r, c ;

Matrices - Addition, Multiplication,

Chess

Q

Q

Q

Q

Q

Q

Q8 8Board

Determinant,Transpose, Inverse etc .

main( )

{

char name[ ] = { ‟S‟, ‟a‟, ‟n‟, ‟j‟, ‟a‟, ‟y‟, „\0‟ } ;

int i ;

for ( i = 0 ; i <= 5 ; i++ )

printf ( ”%c”, name[ i ] ) ;

i = 0 ;

while ( name[ i ] ! = ‟\0‟ )

{

printf ( ”%c”, name[ i ] ) ;

i++ ;

}

}

name[ i++ ]

main( )

{

char name[ ] = { ‟S‟, ‟a‟, ‟n‟, ‟j‟, ‟a‟, ‟y‟, „\0‟ } ;

int i ;

printf ( ”%d%d”, ‟\0‟, ‟0‟ ) ;

0 48

i = 0 ;

while ( name[ i ] ! = 0 )

printf ( ”%c”, name[ i++ ] ) ;

}

i = 0 ;

while ( name[ i ] )

printf ( ”%c”, name[ i++ ] ) ;

Two More Ways

for ( i = 0 ; i <= 5 ; i++ )

while ( name[ i ] ! = ‟\0‟ )

while ( name[ i ] ! = 0 )

while ( name[ i ] )

printf ( ”%s”, name ) ;

Which Is Best?

char str1[ ] = { ‟S‟, ‟a‟, ‟n‟, ‟j‟, ‟a‟, ‟y‟, „\0‟ } ;

char str2[ ] = ”Sanjay” ;

printf ( ”%d%d”, sizeof ( str1 ), sizeof ( str2 ) ) ;

printf ( ”Enter name & surname” ) ;

scanf ( ”%s”, str3 ) ;

printf ( ”%s”, str3 ) ;

printf ( ”Enter name & surname” ) ;

printf ( ”%s”, str3 ) ;

gets ( str3 ) ;

}

char str3[ 15 ] ;

7 7

Rahul

Rahul Sood

Multiword Stringsmain( ){

Rahul Sood

Rahul Sood

puts ( str3 ) ;

3

3.0

‟3‟

”3”

Different

\0 Assumed

StringTerminator

char str1[ ] = ”Amol” ;

char str2[ ] = ”Sanjay” ;

printf ( ”%s%s%s”, str1, str2, str3 ) ;

gets ( str1 ) ;

gets ( str2 ) ;

gets ( str3 ) ;

char str3[ ] = ”Rahul” ;

Which Is Better?main( ){

puts ( str1 ) ;

puts ( str2 ) ;

puts ( str3 ) ;

scanf ( ”%s%s%s”, str1, str2, str3 ) ;

}

strlenstrcpystrcat

struprstrlwrtouppertolowerstrcmpputsgets

strncpy ( str1, str2, 5 ) ;strncat ( str1, str2, 6 ) ;strncmp ( str1, str2, 6 ) ;strncmpi ( str1, str2, 4 ) ;

strnicmp ( str1, str2, 4 ) ;

strchr ( ”Hello”, ‟e‟ ) ;

strstr ( ”I am a boy”, ”am” ) ;strsetstrnset. .. .. .

Standard Library Functions

Is there any error here?

f(int a, int b) {• int a;

• a=20;

• return a;

}

int main() {• int a = 10;

• void f();

• a=f();

• printf (“%d\n”, a);

• return 0;

}void f() {

• printf(“Hi”);

}

int main() {• int i=1;

• if(!i) printf(“Hi\n”);

• else { i=0;

printf(“Hello\n”);

main();

• }

• return 0;

}

int main() {• int fun (int);

• int i=fun(10);

• printf(“%d\n”, --i);

• return 0;

}

int fun (int i) {• return (i++);

}

int main() {• int k=10;

• k=func1(k=func1(k=func1(k)));

• printf(“k=%d\n”, k);

• return 0;

} int func1(int k) {

• k++;

• return (k);

}

int fun(); int i; int main() {

• while(i) { fun();

main();

• }

• printf(“Hello\n”);

• return 0; } int fun() {

• printf(“Hi”);

• return 0; }

int main() {• int i=10, j;

• j=f(i);

• printf(“%d\n”, j);

} int f (int j) {

• int k=3;

• j = j*k;

• return (j,k);

}

Every function must return a value – T or F?

Default return type of a function?Re declaration of a function is an error – T

or F?Re definition of a function is an error – T

or F?There should be only one return

statement in a function – T or F?Problem with TOO MANY recursive calls?

int main() {• int arr[2][] = {

{1,2,3,4,5},

{6,7,8,9,10}

• };

• return 0;

}

Is something wrong?

num[1] means the very first element of

array called num – T or F?

int num[2][4] can also be thought of as

two arrays of 4 elements each – T or F?

int main() {• int arr[1]={10};

• printf(“%d\n”, 0[arr]);

• return 0;

}

What‟s the output?

int main() {• int arr[]={2,3,4,1,6};

• printf(“%u %u %u\n”, arr, &arr[0], &arr);

• return 0;

}

What‟s the output if base address is

275676?

int main() {• int a[5] = (5,1,15,20,25}

• int i,j,m;

• i=++a[1];

• j=a[1]++;

• m=a[i++];

• printf(“%d %d %d\n”, i,j,m);

• return 0;

}

int main() {• char s[] = “abcdef ghi jkl”;

• printf(“%s\n”, &s[2];

• printf(“%s\n”, s);

• printf(“%s\n”, &s);

• printf(“%c\n”, s[2]);

• return 0;

}