C Language Tutorial on Functions Categories for Beginners Session - 11 Video Lecture | Basics of C Language - Fundamentals of Programming - Software Development

in the lesson in the levant session will
go for the second half of the functions
functions and its categories function
without arguments and width return
without return values these are simple
functions like function which takes no
arguments and which have no return which
return nothing for example and I say
void main I say function I am calling a
function and the function I simply say
printf in function so it's quite simple
that this is a function f here is a
function which takes no arguments and
which returns nothing so it is clear
that in the set of braces if I say
nothing it takes zero arguments and if i
don't use any return statement it
returns nothing a quite simple function
functions with arguments and without
return value i pass an argument consider
I which holds three at the beginning now
I say I over here because I is an
integer receive it or here with another
integer it can be i J or it can be I the
name cannot can differ or it can remain
the same in function person d the
percent is for j into j so here i am
calling the function and i am passing
three and i am receiving in j so i will
be printing that square over here so in
function nine is the output instead of
initializing my variable I i'll scan it
over here scanf person t comma ampersand
I now the value whatever I give
is stored in the address of I and is
passed to the function so even if I say
five it will display in function 25 so
this is a program in which I am passing
an argument and I am returning nothing
so this is the second type the first
type is passing nothing and Ritter
nothing and the second type is passing
an argument without written statement
and now comes functions with arguments
and with return value instead of
calculating over here I will return the
calculator value written j into j now
because i am returning some value i need
to hold it in another variable as holds
that other variable know when i say
printf in main person d that is s so i
am calling the function and i am passing
an argument I whatever user gives a
store it in the address of I and I
passed that value J receives it the
calculation j into j happens and i am
returning it so i need to soar it in
other variable s which i am pretty as
holds the square of the given variable
one main important thing to note about
when we are returning something when we
are using the return statement it is
mandatory to say what type are we
returning because jay is of type integer
j into j also returns an integer so say
int if I returning a float I need to say
float but because this is an integer
i'll stick to integer the value let it
be nine in maine it's 81 so if you
return nothing then say white if you
return something then say what type are
you returning is it an integer than
return integer if it is a float then
return float
here is the example of his along with
syntax function with arguments and
without return values function name and
the argument list number of arguments
can be passed the data type usually
avoid an argument list and so on the
statements wat all you feel function
with arguments and with written values
function name the number of arguments
you want to pass data type arguments and
so on return the value at the end
calling functions we can call functions
by two ways first one is called x value
will go for seeing what exactly call by
value and this is a call-by-value
example but let me take a very good work
good example one in Maine which returns
nothing and so void has been used I have
integer within and J with 20 when I say
printf in Maine for the first time I
holds the value person D&J holds a value
person d that is her i comma j i call
the function and pass i comma j so in
function which also returns nothing but
receives two integers in I and J it can
be anything it can be exercising now in
I I will be placing the incremented
value likewise NJ I will be placing the
incremented value Noel print in function
i equal to % e j equal to percent a
comma a comma j after that if i say
printf it mean for the second time I
holtz person d.j holes person day come I
comma J now if you see what exactly
happens in this program is integer I
which holds 10 at the beginning and
integer J which holds 20 I will be
renting a 10 and 20 on the screen I am
passing the earliest 10 and 20 to the
function there the 10 and 20 are again
received in int which are of different
variables 10 plus 1 11 into I 20 plus 1
21 into general print in function 11 and
21 after coming back to nine main if I
execute this printf statement I won't be
getting 10 and 20 so I I will be getting
10 and 20 even if I do some kind of
manipulations on inj though they are not
reflected in the main functions even the
changes what all we are doing on the
function are not affecting my main
function this is called as call-by-value
well when we go for call by reference
the exact thing happens but before going
for call by reference we need to take up
a new car topic called as pointers that
we'll see in further sections but before
that there is another topic in functions
which is called as recurrence functions
a recurrence function can be defined as
a function which calls itself again and
again for certain number of times that
is called as recursive function will see
with an example
this program execution begins from Maine
there I have a call to function so i
will go to function and again in that
function i am calling the same again so
i will go back to function for the
second time calling it going back to the
function will 30 so there is this is a
never-ending program this is an
indefinite function call so i said of a
recursive function is nothing but
calling the function itself or some
number of times but how exactly is it
possible because it is making it an
indefinite call so recursive function by
nature is an indefinite function call to
make it definite we need to use and
if-else condition now the recurrence
function can be better explained by
taking up two programs one is the one we
already did that was the factorial
program and the other the new one which
we'll see later on so i will be using
the factorial program with recursive
concept now as we did then a factorial
program normally to repeat the loop i
ask the user to scan some value scanf
person d comma ampersand and now the
value what user has given is stored in a
variable and call the function and pass
n and it returns certain value which
will be given to the variable F so I'm
printing person d comma f declare the
variable
now in the function as I said it returns
something and is given into F so it
means that the function definition
should be integer function because it
returns something and we are passing a
variable the value given by user that is
an receive it in same variable or
different variable check if and less
than or equal to 1 return one else
return n into function of n minus 1 so
here consider if your value given by
user is Phi we say function Phi we are
passing 5 and so it receives it five
less than one is false so you will come
to us block 5 into now cause again
calling the same function you are in the
function and you are calling the same
function so this time 5 went over the
argument is Phi minus 14 so you will go
over here with the value and take 44
less than one is false previously it was
5 into now this time it is for into fact
of 3 1 of 3 so it is 5 into 4 into 3
into 2 into 1 finally do the
multiplication and give it to the
variable X printing it on the screen if
my input is phi i will be getting the
mistake done worse f takes one at the
beginning place one or simply leave f in
the same way we will be getting the
factorial even gives 687 20 so this is a
concept of factorial programming by
using recursive call it is passing the
value you say you check it five less
than one false come to us block five
into fat fun of for gopher one of four
for less than one falls now this time 4
into 5 into 4 into 1 of 3 so like what
it will
keep on calculating the values until
unless the value of n is not less than
or equal to 1 similarly using the
recursive call in a new program called
as Fibonacci series whose output should
be will be beginning with 0 & 1 later on
displaying 1 2 3 5 & 8 13 21 but on what
basis i am saying all this series this
series is called as Fibonacci series
Fibonacci series so I said we'll be
starting up with 0 + 10 + 1 1 1 plus 1 1
plus 1 2 1 + 2 3 2 + 35 3 plus 5 85 + 8
13 13 + 10 8 21 so this way will be
printing all our series set up it is 0
and B with one C takes the addition and
will place a while condition which says
the number of iterations while I begin
with one and the condition I less than
or equal to 10 and in that say C takes
of the addition of a plus B printing
visente comma C it prints the addition
so we'll be skipping up saying 0 and 1
as they are already defined will be
starting up with all this series 1 2 3 5
8 and so on so one is on the screen 0
plus 11 is on the screen now we need to
interchange the values as this is a and
B now we need to add these so to get the
C value but this is V and this is C so
make be as a what I'll be ho
give it to a and what all she holds give
it to be and repeat the loop making i
plus plus so it will print all the
series which comfortin limit this is
called as Fibonacci series now doing the
same thing in by using the recursive
call which goes in this way integer a
takes 0 comma B takes one so an integer
variable to repeat the loop let it begin
with one while I less than or equal to
10 and say call the function pass the
value I which returns some value so I
accepted in F a variable and print it on
screen increment the value of Phi back
in the function this int function
receive it in the variable I or any
other thing if I is less than or equal
to 1 return one else return fun of I
minus one plus one of I minus two is
what we need to return so what exactly
we mean by this so you can see the
values have been printed in Fibonacci
series but how exactly is this working
now as you can see I begins with one
which holds one less than or equal to 10
that is true so pass one so I receives
the variable 1 1 less than or equal to 1
yes loooser return one later on that
return value is given in to the variable
F and is printed on the screen later on
I plus plus happens so this time is to
tool ascent and yes it's true so pass
the value to I receives the value to 2
less than or equal to 1 is false now
come to else block here fact of 2-1 that
is one fact of 1 plus factor 0 what is
fact of one we need to find it out so
again I am calling the same function i
mean the function and calling the same
function this time I receives 11 less
than 1 is 1 yes return 1 this is for
this particular block what about fact of
0 I received 0 0 less than 1 yes written
one so finally I will be retaining 1
plus 1 which is too and is printed
returned to the variable F and a
sprinter on the screen now I plus plus
happens making it as me so likewise this
works for up to 10 calls finally
printing all the Fibonacci series