reUOojtbU3A&ab_channel=IITMadras-B.S.DegreeProgramme_transcript.txt

[Music]
hi my name is Venkatesh and my name is
Madhavan together we are going to
introduce this course which is called
computational thinking to you which is
the first starting step to learning
programming actually and the reason we
are calling it computational thinking is
because before we start doing any
programming work we got to organize our
thinking in a very specific way so that
this thinking process is systematic and
can be communicated to another person or
to a computer or whatever it is for
which thought process has to be
organized in a very very specific way
and all that we will teach you in this
course essentially is to help you to
organize your thought process like this
so we must remember that a computer is
just a very precise machine which can
execute some commands that we tell it to
like to add some numbers or to divide
some numbers or to move things around
you know rearrange something so what we
are really doing when we instruct a
computer through a program is to follow
a specific sequence of steps to achieve
some goal so this is nothing very
special about computers the same thing
happens when we talk to somebody else
about how to do something for instance
if you have ever experienced cooking
show or cooked yourself then you would
follow a recipe so a recipe for cooking
is just a sequence of steps it tells you
what are all the ingredients that you
need then it will tell you how to
process these it'll tell you something
fine it will tell you to make put
something into a mixer and grind it into
a powder and then it will tell you to
heat something put something there will
be a sequence you add something first
add something second and of course how
much detail these instructions are
depend on what is the expected
understanding of your level of expertise
so if I think you are an expert cook I
would just say chop something fine but
if I think that you are cooking for the
first time then I might tell you that by
fine I mean that each piece must be
roughly say two millimeters by two
millimeters or it should be five
millimeters by five millimeters so let's
take an example suppose
trying to arrange a function in a hall
and I want to get this hall ready for
the function so if this if there is a
team of people who do this regularly
right then I just have to tell you know
the function is going to start at 10
o'clock tomorrow there will be 50 people
please get the hall ready and this will
be enough but supposing this is a new
team of people who have never done this
before then I have to be much more
elaborate I will have to say maybe that
you should make sure that the hall is
cleaned half an hour before if it is
warm weather maybe turn on the
air-conditioner at 9:30 then if they're
supposed to be fifty people how do you
arrange the chairs I might have to say
put the chairs in 10 rows but or in five
rows with 10 chairs per row but then
keep a gap in the middle so you have
five gap and five so depending on how
much I expect the person who is going to
understand and do the instruction
execute the instruction how much they
can do without further explanation I
will give a suitable level of
instructions so this is what we do when
we talk to computer so we tell it
certain steps and those steps are based
on our understanding of what the
computer can do easily like I had
subtract you know flip left and right
and so on so this is the language of
talking to a computer and this is
programming so in this course we are not
really going to talk about specifically
programming in any one language we are
going to discuss rather the general
steps that we use when we do
computational things which will
eventually be done on a computer so as
modern explained the whole idea of doing
programming is to convert a given
problem into a sequence a procedure
which is a basically a sequence of steps
and what we will find
while we do this course what we'll find
interesting is that there is a pattern
for a problem when you look at a problem
the problems don't all look very
different actually they all fall into
certain patterns and when I say patterns
what it means basically is that the
sequence of steps for one problem can
look very similar to the sequence of
steps that we use to solve another
problem and so basically if you do one
pattern if you find for a signal
we find the pattern which is what kind
of steps that we need then one might be
able to take these steps and apply them
to a completely different problem coming
from a very different problem domain
right and this pattern can be simple for
simple problems and can be extremely
complex for complex problems so there
can be a gradation in the complexity or
the difficulty of the the pattern right
in some sense so just as an example
consider for example you know at home
the dry clothes and so on so we get the
clothes from the dryer from the washing
machine so it has in a bucket or in a
tub and we have these clotheslines and
we need to take out these clothes and
hang them on the clothesline so if we go
about it in episode Li you might take
the clothes and hang them and then after
you start hanging them on the
clothesline you'll find there is there
are gaps between the clothes that they
are hung there and so you have to find
the appropriate cloth that will go in
that gap right so to make it easier what
you might say is that let me start to do
it in a more systematic way so let me
start in the clothes line from the left
to the right so I take the biggest piece
of cloth that is there hang it on the
left side put a clip then pick the next
biggest one put it next to it put a clip
and go like that at the end when I have
a small piece of space I will find the
most appropriate you know cloth that can
hang in that place and so I fill that
clothesline and then move to the next
clothesline so that can be one way of
doing it so this is a pattern this gives
me a pattern so the pattern basically
says look for the biggest piece of cloth
hang it on the left side of the plots
length is a pattern now if you look at
another problem for example I have a
bunch of books that I have in a box and
I have a three shelves and I want to put
these books on a shelf again I have to
do something right I have to pick
something and put it on the shelf again
I can do it oppositely or I could do it
systematically I can take the biggest
book keep it on the left side with the
first shelf and then put the next
biggest book with next to it and so on
and go like that and if you look at the
pattern for the books looks very similar
to the pattern for the clothes how you
hang the clothes on the line so in a
sense there is even though the problem
statements are very different right one
is saying arrange books on a shelf the
other problem is saying hang the clothes
on a line the prob the way you approach
these problems can look very very
similar and a single part
turn you might be able to write which
does both so that is what we are going
to explore in this course how do we find
these kind of patterns which solves a
very large class of problems coming from
different domains so in order to
illustrate these patterns and how we
move from simple problems to more
complex problems what we will do is we
will work with some sets of data so in
our next lecture we will look at these
data sets in detail and explain exactly
what we are going to do but just to give
a quick introduction we have these cards
so we have some data about school marks
so we have cards representing the marks
of students in a class we have some
shopping data which talks about shopping
bills and how customers spend on their
bills and when we have some data taken
from a paragraph if text where we talk
about words and how many letters there
are in each word and what type of speech
and all that and using these different
very simple pieces of data we will
illustrate these ideas about looking for
patterns and computing quantities in a
systematic way