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uh hello guys uh welcome to this video
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so in this video I will show you a very
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common program which is asked inside
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placements or interview questions for
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GATE uh for competitive exams it's
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called as Fibonacci sequence or pattern
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if you want to print this uh fib fiboni
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sequence or pattern it's a very special
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pattern where uh the next number is
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the sum of the previous two numbers so
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basically this is actually the pattern
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so if I just write let me just open the
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zoom it tool on my machine so that I can
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zoom on particular element so just
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wait so this is essentially this pattern
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if you just write
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01 so as you can see these are the first
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two numbers in the pattern 0 1 and this
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third number is the sum of the previous
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two numbers this is 0 + 1 which comes
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out to be 1 and now the next number
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which will come in the pattern which it
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will be the sum of these two numbers
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which will be 1 + 1 and this comes out
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to be two and now the next number will
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be the sum of these two numbers which
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will be 1 + 2 which will be three and
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now this will be the sum 2 + 3 as you
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can see this is actually the pattern
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which is called as Fibonacci sequence or
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pattern and now we just need to print
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this pattern using a Python program so
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this Python program executes like this
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so if I try to execute this program so
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Python app py it will ask me to the
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enter the number for fibonaki sequence
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so how many sequence you want to print
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out so I will say I want to print the
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pattern up till
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10 or five numbers so it will print out
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the pattern here you can see 01 the next
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number is the sum of this first two
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numbers and the next number is 1 + 1 2
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and then 2 + 1 3 so this is the thing if
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you say 10 you will see again it follows
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the same
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pattern so now I will show you the
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Python program how to build this so the
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very first thing we need to realize that
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in this pattern the first two numbers
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are constant which is 0 1 so
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irrespective of how many sequence I want
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to print out these two numbers are
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printed like this
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01 so let me first of all write this
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program so here we will be accepting the
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user input so for this we will be type
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casting the value here to integer and we
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will ask the question to the user that
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enter the number for
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Fibonacci
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sequence so now the user writes the
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number and right here we will create two
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variables a is equal to zero and b is
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equal to 1 so these two numbers will be
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printed out irrespective of how many
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uh digits you get so these two numbers
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are constant so we just need to print
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these numbers like this so print the
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first number so here we need to print
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like this the first number and the
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second number
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but the problem here is that if I try to
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execute this this appears on next line
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like this 01 but if you want to print
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side by side there is a end function
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that you can use put a comma and then
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you can put a end symbol is equal to
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double quote so this means that it
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will appear both these characters will
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appear side by side if you want some
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space then you can add some space here
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so we can add some space like like
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this so this means that both these
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numbers will appear side by side so in
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this way you can do this so if I try to
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execute this now you will see 01 is
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printed out and now we need to use the
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for loop for printing out the other
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numbers so for this we will use the for
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loop for i in range range so it will run
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from the second index up till the total
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number of numbers that it receives so
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let's suppose I provide five here it
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will run up till
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2 5 five is not included because this
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number is not included so it will run up
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till 2 n minus one so 2 to
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4 so inside this for loop what we need
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to do we need to calculate the sum of
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the these two numbers as you can see 0 +
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1 which will give you the third number
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which will be 1 for this we will be
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using the third variable so we create
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this third variable we calculate the sum
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which will be a + b and then we store
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this sum inside this third variable c
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and whatever is the sum right here and
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for
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this one more thing so if I try to print
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this number like this if I print this
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you will see the problem which will be
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there if I print this C number and if I
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run this now you will see the pattern
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will not be printed out you will see 0
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1 up till now this the pattern is
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correct because 0 + 1 comes out to be
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one but here also the next number is
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also one the next number is also one so
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now we need to make sure that we also
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switch the value of uh a and b because a
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and b is set to zero and one so we need
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to make sure that uh uh the values of a
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and b in the next iteration of when we
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move the index to the sec uh next number
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when we go to the third index this third
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number we need to make
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sure a is set to this number and b is
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set to this for doing this we need to
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swap the index here for doing this we
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simply say a is equal to
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b and b is equal to c so this is a
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swapping that we are doing right here
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using a third variable so we calculate
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the sum and then we make sure that we
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interchange the
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indexes the next the second number
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becomes the first number and then the
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sum of these two numbers becomes the
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second number so now if you run this
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pattern you will see the correct pattern
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will be printed out you will see 0 1 the
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sum of these two numbers comes out to be
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the third number and then we move to the
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next number which is 1 + 1 2 and then 1
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+ 2 3 this is essentially this pattern
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comes out to be and if I let's suppose
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you can see this is 10
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numbers 1 + 1 2 2 + 3 5 5 + 8 13 + 8 21
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+ 13 34 now this is the way by which you
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can print out this Fibonacci sequence or
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pattern this is asked inside various
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competitive exams such as in coding
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placements as well so GATE exams as well
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so in this way you can uh write this
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program in Python and thank you very
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much for watching this video please hit
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that like button subscribe the channel
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and also check out my website
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freemediattools.com
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uh which contains thousands of tools