Lucky Lecture Yes Yes s

8/16/2019 Lucky Lecture Yes Yes s

1/54

Asif Nawaz PMAS UAAR University Institute of Information Technology

Lecture 0 ! Programming "un#amentals ! 0$%


Lecture $&

"unctions

$


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User 'e(ne# "unction


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• A user)#e(ne# function consists ofthe following!

– "unction 'eclaration may also *e calle# as"unction Prototy+e

– "unction 'e(nition

&


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"unction'eclaration,Prototy+e

"unction +rototy+e +rovi#esinformation to the com+iler a*out thestructure of the function to *e use#in a +rogram-

Rules! – Usually placed at the beginning of source

file just before the main() function. – Must be ends with a semicolon.

%


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"unction'eclaration,Prototy+e

• "unction 'eclaration consists of thefollowing +arts-

– "unction Name – "unction Return Ty+e- – Num*er an# Ty+es of Parameters-

.here !Return Ty+e in#icate the ty+e of value that will *e returne#*y function-Parameters are the values that are +rovi#e# to a functionwhen the function is calle#-

/


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1am+le

The following function show that thefunction show acce+t no +arameter an#no return ty+e-

void show(void);

The following function show that thefunction sum acce+t integer +arameter

an# integer return ty+e-

int sum(int);

2


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1am+le

The following function show that thefunction a## acce+t three integer+arameter an# integer return ty+e-

int add(int a, int b, int c);

3


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"unction 'e(nition

• A set of statements that e1+lainswhat a function #oes is calle#function #e(nition-

Rules! – Usually placed after the main() function.

4


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"unction '(nition

• The function #e(nition consists of two+arts-

• "unction 5ea#er! – "irst line of function #e(nition- – Similar to function +rototy+e *ut with no semicolon- – Num*er of +arameters an# return ty+e will *e same

as +rototy+e-

• "unction 6o#y! – The set of statements which are e1ecute# insi#e

function- – The *o#y will always a++ear after function #eclarator

an# statements are written in curly *races- 7


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Synta1 "unction 'e(nition

Return !ype "unction #ame($arameter)

%

&tatement ';

&tatement ;

.

.

.

&tatement #;

$0

"unction5ea#er

"unction6o#y


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"unction 8all

• The statement that activates afunction is 9nown as function call-

• A function is calle# with its name an#+arameter list-

• .hen "unction is calle# then! – The control moves to the function that is calle#- – All statements in the function *o#y are e1ecute#- – The control returns *ac9 to the calling function-

$$


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$

main: ; <===-===-"un: ;>===-

===-"un: ;> ?

voi# "un: ; <

==--==--

?

8alling"unction

"unction8alls

8alle# "unction


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.rite a +rogram that #is+lay amessage @Programming is anInteresting "iel# on screen *y usingfunction-

$&


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void show(void);

main()

%

show();getch();

void show(void)

%

cout**+ Programming is an interesting field” ;

$%


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1am+le

.rite a +rogram that a## two integernum*ers- the num*ers shoul# to thefunction as argument-

$/


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$2

void sum(int , int );

main()

%

sum(' , '-);

cout** /0 ;getch();

void sum(int 1, int y)

%

int s 2 1 3 y;

cout** &um is 2 **s**endl;


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Passing Parameters to a"unction

• Two ways to +ass values to functionBsParameter!

» Pass *y value-» Pass *y Reference-

$3

$


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Pass *y Calue

A +arameter +assing mechanism inwhich the value of actual +arameteris co+ie# to formal +arameter ofcalle# function is 9nown as +ass *yvalue-

$4

0 i l 0$%


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1am+le

$7

.rite a +rogram that in+ut twointeger num*ers in main: ; functionD+asses these num*ers to function-

The function #is+lays the ma1imumnum*er-

L 0 ! P i " # l ! 0$%


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void ma1(int a,int b );

main()

%

int 1, y;cout**+4nter two numbers ;

cin55155y;

ma1(1,y);

getch();

void ma1(int a, intb)

%if(a5b);

% cout**+Ma1 number is **a**endl;

else cout**+Ma1 number is **b**endl;

0

L 0 ! P i " # l ! 0$%


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1am+le

$

.rite a +rogram that in+ut a num*erin main function an# +asses num*ersto a function- The function #is+laysta*le of that num*er-

L t 0 ! P i " # t l ! 0$%


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void table(int n);

main()

%int num;

cout**+4nter number fortable ;

cin55num;

table(num);

getch();

void table(int n)

%for(int c2 ; c*2' ; c33)

%

cout**n**+6+**c**+2+**n6c**endl;

?

L t 0 ! P g i g " # t l ! 0$%


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1am+le

&

.rite a +rogram that in+ut a num*erin main function an# +asses num*ersto a function- The function #is+laysfactorial of that num*er-

Lect re 0 ! Programming " n#amentals ! 0$%


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1am+le

.rite a +rogram that in+ut twonum*ers an# one arithmetic o+erator+asses from main to function- Thefunction a++lies arithmetic o+erationon that two num*ers *ase# on theo+erator enter *y the user using

switch statement-

%



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void operation(int a, int b, char ope)

%

switch(ope)

%

case 7389

cout** a**+3:**b**a3b;

brea0;

case 7 89

cout** a**+ :**b**a b;

brea0;

case 7689

cout** a**+6:**b**a6b;

brea0;

.

.

.

default9

cout**+ nvalid /perator


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Lecture 0 ! Programming un#amentals ! 0$%

Pass *y Refrence

2

A +arameter +assing mechanism inwhich the value of actual +arameteris +asse# to the calle# function is9nown as +ass *y value- The formal+arameter is not create# se+aratelyin the main memory-



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1am+le

Program to swa+ values using +ass *yreference-

3



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4

void swap(int =>, int =y);main()

%

int a,b;

cout**+4nter values:;

cin55a55b;cout**+?alues before swap9:;

cout**+a 2+**a**endl;

cout**+b 2+**b**endl;

swap(a,b);

getch();cout**+?alues after swap9:;

cout**+a 2+**a**endl;

cout**+b 2+**b**endl;

getch();

void swap(int =1, int =y)%int t;

t 2 1;1 2 y;y 2 t;



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Returning Calue from a"unction

.rite a +rogram that in+uts mar9s inmain function an# +asses these mar9sto a function- The function (n#s gra#eof a stu#ent on the *ases of followingcriteria-

Era#e A 40 or A*ove mar9sEra#e 6 20 to 37 mar9sEra#e 8 %0 to /7 mar9sEra#e "*elow %0 mar9s

7



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&0

char grade(int m);

main()

%

int mar0s;

char g;

cout**+4nter mar0s:;

cin55mar0s;

g 2 grade(mar0s);

cout**+@our grade is:**g;

getch();

Ahar grade(int m)

%

if(m5B )return 7C8;

else if (m5D )return 7E8;

else if (m5F )

return 7A8;else

return 7"8;



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.rite a +rogram that in+uts *ase an#height in main function an# +assesthem to a function- The function (n#sthe area of a triangle an# return it toa main functionD where it #is+lay onscreen-

Crea is 2 G (Ease 6 height)

&$



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&

float triangle(int b, int h);

main()

%

int base, height;

float area;

cout**+4nter base:;

cin55base;

cout**+4nter height:;

cin55height;

area 2 triangle(base, height);

cout**+Crea is:**area;

getch();

float area(int b, int h)%

float a;a 2 .- 6 b 6 h;return a;



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&&

.rite a +rogram that in+uts twointeger- It +asses one integer to thefunction that calculate an# return itssFuare- It +asses secon# integer toanother function that calculate an#return its cu*e- The main function

a## *oth values an# return its result-



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&%

int sHuare(int n);

int cube(int n);

main()

%

int a, b, sum;

cout**+4nter first nteger:;

cin55a;

cout**+4nter &econd nteger:;

cin55b;

sum 2 sHr(a) 3 cube(b);

cout**+Result is:**sum;

getch();

int sHuare(int n)%

return n 6 n;

int cube(int n)

%return n 6 n 6 n;



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Sco+e of Caria*le

• The varia*les can *e #eclare# insi#ethe main functionD insi#e user#e(ne# function-

• The eGect of the varia*les #eclare#in these +laces is #iGerent-

• 6ase# u+on their eGectsD varia*lesare #ivi#e# into two classes!

• Local Caria*le• Elo*al Caria*le

&/



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ectu e 0 ! og a g u a e ta s ! 0$%

Local Caria*le

• The varia*le #eclare# insi#e the mainfunction or insi#e user #e(ne#function is calle# Local Caria*le-

These varia*les may also *e calle#as Automatic Caria*les-

&2



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g g $

&3

void sum(int , int );

main()

%

int a 2 - ;

int b 2 D ;s 2 sum(' , '-);

cout**+&um is 2+**sum;

cout** /0 ;

getch();

void sum(int 1, int y)%int s 2 1 3 y;return s;



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g g

Elo*al Caria*le

&4

• The varia*le #eclare# outsi#e themain function or any other user#e(ne# function is calle# glo*alCaria*le- These varia*les can *eaccesse# in any function at any time#uring the e1ecution of +rogram-



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g g

1am+le

&7

int g;

void fun(void);

main()

%

cout**+ 4nter a number +;cin55g;

cout**+?alue of g before function:**g;

fun();

cout**+?alue of g after function:**g;

getch();

void fun()%

g 2 g 6 ;



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g g

'efault Parameter

• The +arameter that initialize #uringfunction #eclaration is calle# #efault+arameter-

%0



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g g

%$

void !est(int n 2 ' );

main()

%

!est();

!est( );!est(I-);

getch();

void !est(int n)

%

cout**+n2 **n**endl;

Output:

1002

75



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Asif Nawaz PMAS UAAR University Institute of Information Technology %

void add(int v'2-, int v 2 ' );main()

%

int vJ 2 v' 3 v ;

cout**+!he sum of two num 2+**vJ;getch();

void !est(int n)

%

add();add(', );

add(');

Output:

!he sum of two num 2 '-

!he sum of two num 2 J!he sum of two num 2 ''



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"unctions an# Arrays

• An array can *e +asse# to a functionas a +arameter-

• .hen an array is +asse# as a+arameter to a functionD only thea##ress of (rst element of the arrayis +asse#-

• An array is +asse# *y reference not*y value-

void display(int arrayKL); %&



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1am+le

.rite a +rogram that in+uts (veinteger in an array an# +asses thearray to a function- The function#is+lay the value of the array-

%%



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Asif Nawaz PMAS UAAR University Institute of Information Technology %/

void show(int arrayKL);

main()

%int numK-L, i;

cout**+4nter five nteger ;for(int i2 ; i*2-; i33)

%

cin55numKiL;

show(num);getch();

void show(int arrayKL)

%

int j;for(int j2 ; j*2-; j33)

%

cout**arrayKjL**endl;

?



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1am+le

%2

.rite a +rogram that in+uts (veinteger in an array an# +asses thearray to a function- The functioncounts the even num*ers in thearray- An# return the result to mainfunction where the result is

#is+laye#-



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Asif Nawaz PMAS UAAR University Institute of Information Technology %3

int even(int arrayKL);main()

%int numK-L, i, n;

cout**+4nter five nteger ;

for(int i2 ; i*2-; i33)%

cin55numKiL;

n 2 even(num);Aout**+!he array

contain**n**+even number:;

getch();

int even(int arrayKL)

%

int j, e;

e 2 ;for(int j2 ; j*2-; j33)

%if(arrayKjL 22 )

%

e33;

?



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"unction an# Structure

• The structures can also *e use# withfunction-

• A function can acce+t structure as+arameter-

• A function can also return a structurevaria*le-

%4



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1am+le

.rite a +rogram that #eclares astructure to store mar9s an# gra#e- It#e(nes structure varia*le an# in+utvalues- It +asses the varia*le to afunction that show its contents-

%7



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Asif Nawaz PMAS UAAR University Institute of Information Technology /0

void show(!est p);

main()

%

struct !est

%

int mar0s;

char grade;

;

!est t;

cout**+4nter mar0s:;

cin55t.mar0s;

cout**+4nter grade:;

cin55t.grade;

show(t);

getch();

void show(!est p)%cout**+Mar0s:**p.mar0s**endl;cout**+Nrade:**p.grade**endl;



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Asif Nawaz PMAS UAAR University Institute of Information Technology /$

.rite a +rogram that #eclares astructure to store country name an#+o+ulation in million- It #e(nes twostructure varia*le an# in+uts values-It +asses *oth varia*les to a functionthat show the recor# of a country

with more +o+ulation-



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Asif Nawaz PMAS UAAR University Institute of Information Technology /

void fun(pop 1, pop y);

main()

%struct pop

%

char name;

float people;

;pop a,b;cout**+4nter Aountry #ame

= population:;

cin55a.name55a.people;

cout**+4nter Aountry #ame= population:;

cin55b.name55b.people;

fun(a,b);

getch();

void fun(pop 1, pop y)%cout**+!he country withmore population 9:;%

if(1.pp5y.pp)%cout**+#ame:**1.name**endl;cout**+$opulation:**p.population;else

cout**+#ame:**y.name**endl;cout**+$opulation:**y.population;



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"unction Hverloa#ing

• "unction with same name *ut with#iGerent +arameters value is calle#function overloa#ing-

• The function with same name may*e #iGerent with one of the followingways-

» Num*er of +arameters» Ty+e of +arameter» SeFuence of +arameter

/&



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void line();

void line(int n);

void line(int n, c ar c);

main()

!struct "est!

line()line(#);

line(5, $ @ %);getc ();&

void line();!

int i;

for(i'1; i '10; i )

!cout * + * endl;

&

void line(n);

%

int i;

for(i2n; i*2' ; i33)

%

cout**+ 6 +**endl;

void line(int n, char c);

%

int ;

for(i2'; i*2n; i33)%

cout**c**endl;

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