i unit _ cds material

8/12/2019 i Unit _ Cds Material

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UNIT I

1. a) What is an algorithm? Write the variouscriteria used for judging an algorithm.

1. Step by step Procedure to solve a Particular problemis called ALGORITHM

2. Alorit!m ca" also be called as Pseudo # $ode%. Alorit!m ca" be de&"ed as a 'ell#de&"ed

computatio"al procedure t!at ta(es si"le value or aset o) values as i"puts a"d produces a si"le ormultiple values as output.

*. T!us it is a se+ue"ce o) steps '!ic! tra"s)orms a"i"put i"to a" output.

,. A si"le problem may !ave multiple alorit!ms. Also-a" alorit!m is al'ays a la"uae#)ree computatio"alsteps.

. I" order to compare alorit!ms- 'e must !ave some

criteria to measure t!e e/cie"cy o) our alorit!ms.Suppose a" alorit!m !as m i"put data. T!e time a"dspace used by t!e alorit!m are t!e t'o mai"measures )or t!e e/cie"cy o) t!e alorit!m.

0. T!e time is measured by cou"ti" t!e "umber o) (eyoperatio"s i" sorti" a"d searc!i" alorit!ms-

. T!e space is measured by cou"ti" t!e ma3imum o)memory

"eeded by t!e alorit!m.

Characteristics of an Algorithm

4ac! a"d every Alorit!m s!ould satis)y t!e )ollo'i"$riteria5

a. I"putb. Output


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c. 6i"ite"essd. 7e&"ite"esse. 48ective"ess

!"am#le Write an algorithm to $nd the roots of%uadratic e%uation for all the cases.

Step 1: Input A, B, C

Step 2: Set D = B * B 4 * A * C

Step 3: If D > 0 then :

(a)Set X1 = (-B + SQRT(D))/ 2 * A

(b)Set X2 = (-B - SQRT(D))/ 2 * A

(c) Print X1, X2

Else if D = 0 then:

(a)Set X = -B / 2 * A

(b)Print X

Else

Print Roots are imaginary

End If

Step 4: Exit


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1 b)What is a &o'chart? !"#lain the di(erent sm*olsused in a+,-WCA/T.1. A 9o'c!art is t!e pictorial represe"tatio" o) a" alorit!m.2. T!e various steps i" a" alorit!m are dra'" i" t!e )orm o)prescribed symbols.%. T!e 9o' o) t!e alorit!m is mai"tai"ed i" a 9o'c!art.*. T!e various symbols used i" a 9o'c!art are as belo'.


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!"am#le


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0. a. What is a aria*le2 o' it can *e declared2initiali3ed 'ith e"am#les. *. Write a C #rogram to s'a# 0 varia*les using

third varia*le and 'ithout using third varia*le

1. A :ariable !as a "ame a"d type - used to !old somedata temporarily.2. T!e value o) a variable ca" be altered; modi&ed laterat a"y time i" t!e proram%. 7eclaratio" o) a variable5

Sy"ta35

I" t!e above declaratio" a-b a"d c are i"teervariables '!ic! ca" store some i"teer data9oat c-d-e>

I" t!e above declaratio" c-d a"d e are 9oat variables'!ic! ca" store some real data

2. I"itiali?atio" o) a variable5


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i"t a-b-c> ;; a- b- c are declareda@1>b@2>c@%> ;; a-b-c are i"itiali?ed 'it! some values - t!is

(i"d o) i"itiali?atio" is called as static i"itiali?atio" .

a-b-c ca" also be i"itiali?ed dy"amicallyB at ru" timeC

sca")BDEdEdEdF-a-b-cC>

; proram to s'ap 2 variables usi" t!ird variable ;i"clude ;; readi" a-b values at ru"

time

temp @ a>

a @ b>b @ temp>

pri"t)BDvalues o) a a"d b a)ter s'appi" EdEdK"F-a-bC>

etc!BC>

; proram to s'ap 2 variables 'it! out usi" t!irdvariable ;


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i"clude ;; readi" a -b values at

ru" timea @ ab>b @ a#b>a @ a#b>

pri"t)BDvalues o) a a"d b a)ter s'appi" Ed

EdK"F-a-bC>etc!BC>

2 $C. i 43plai"Constants and Different data types.ii In How many ways constants can be defined


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b.

I" t!ree 'ays co"sta"ts ca" be de&"ed i" a $

proramiC usi" de&"e

e35#

de&"e PI %.1*de&"e SIN4 2de&"e A4R DQ4L$OM4F

Q!e"ever 'e use t!e above co"sta"ts t!eoccurre"ce o) eac! PI 'ill be replaced 'it! its value.

iiC usi" (ey'ord co"stco"st i"t si?e@1>co"st 9oat pi@%.1*%2>

iiiC usi" (ey'ord e"um


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e"um dayJmo"-tue-'ed-t!u-)ri-sat-su">e"um oolea" Jtrue-)alse>

4. 5istinguish *et'een the follo'ing6i) Actual and formal arguments

Actual argumentt!ese are t!e arume"ts- '!ic! arespeci&ed i" t!e )u"ctio" call or calli" )u"ctio"435#

a @ cd B3- yC. Here 3 a"d y are called t!e actualarume"ts

+ormal argumentst!ese are t!e arume"ts used i" t!eu"ctio" declaratio".43 5# co"sider i"t cd Bi"t m- i"t "C

J;; code )or &"di" t!e cd )or m-"

Here m a"d " are called t!e )ormal arume"ts

6ii) 7lo*al and local varia*les

7lo*al varia*let!e variables- '!ic! are declaredoutside all t!e )u"ctio"s Bi"cludi" t!e mai"C is- called aslobal variable. T!ey are available to all t!e )u"ctio"s.

435 # i"t a>9oat b>void mai"BCJ

i"t c>c!ar d>


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I" t!e above e3ample a-b are lobal variables-

c-d are local variables.

,ocal varia*let!e variables- '!ic! are declared 'it!i" a)u"ctio"- are called local variables. T!ey ca" be used o"ly'it!i" t!e )u"ctio" i" '!ic! it is declared.

6iii) Automatic and static varia*lesAutomatic varia*let!ey are created '!e" t!e )u"ctio"bloc( is e"tered a"d removed '!e" t!e )u"ctio" istermi"ated. y de)ault- all t!e variables are automaticvariables.

435 mai"BCJi"t a>static i"t b>

I" t!e above e3ample i"t a ca" also be co"sidered as autoi"t a '!ic! mea"s all local variables are automatic byde)ault as t!ey are created a"d deleted automatically.

T!e variable b is a static variable '!ose value 'ill bepersiste"t i" bet'ee" t!e )u"ctio" calls

8tatic varia*lest!ey are variables- '!ic! are declaredlocal to a )u"ctio". Ho'ever t!ey are available eve"outside t!e )u"ctio" i" '!ic! t!ey are declared.

*. rie9y 43plai" $o"trol Structures available i" $la"uae

This deals with the various methods that C can control the flowof logic in aprogram. Control statements can be classified as un-conditional andconditional branch statements and loop or iterative statements. The Branchtype includes:

. !n-conditional:

goto

brea"


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return

continue

#. Conditional:

if

if $ else %ested if

switch case statement

&. 'oop or iterative:

for loop

while loop

do-while loop

Conditional (tatements:

(ometimes we want a program to select an action from two or morealternatives. This re)uires a deviation from the basic se)uential order ofstatement e*ecution. (uch programs must contain two or more statementsthat mightbee*ecuted+ but have some way to select only one of the listedoptions each time the program is run. This is "nown as conditionale*ecution.

if statement:

(tatement or set of statements can be conditionally e*ecuted using ifstatement. Here+ logical condition is tested which+ may either true or false.If the logical test is true ,non ero value the statement that immediatelyfollows if is e*ecuted. If the logical condition is false the control transfers tothe ne*t e*ecutable statement.The general synta* of simple if statement is:

if ,condition statement_to_execute_if_condition_is_true/

or

if ,condition0

statement /statement #/

1 1 1 1/}

Flowchart Segment:


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if $ else statement:

The if statement is used to e*ecute only one action. If there are twostatements to be e*ecuted alternatively+ then if-else statement is used. Theif-else statement is a two way branching. The general synta* of simple if -elsestatement is:

if ,condition

statement_to_execute_if_condition_is_true/else

statement_to_execute_if_condition_is_false/

2here+statementmay be a single statement+ a bloc"+ or nothing+ and theelse statement is optional. The conditional statement produces a scalarresult+ i.e.+ an integer+ character or floating point type.

It is important to remember that an if statement in C can e*ecute only onestatement on each branch ,T or 3. If we desire that multiple statements bee*ecuted on a branch+ we must blockthem inside of a {and }pair to ma"ethem a single compound statement. Thus+ the C code for the flowchart

segment above would be:

3lowchart (egment:

(tatement if

,Condition

T

3


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Example:

main,0

int num/printf,4 5nter a number : 4/scanf,46d7+8num/if ,num 6 # 99

printf,4 5ven %umber 4/else

printf,4 ;dd %umber 4/ / i SS A ;uter loop A0

for ,O 9 / O > U/ O SS A st level of nesting A0

temp 9 /for," 9 / " > O/ " SS

temp 9 temp I/printf ,6dFt+ temp/

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