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How to Swap Two Numbers Without Using Temp Variable in Python – GATE, Interview & Placement Practice
Jun 1, 2025
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0:00
uh hello guys welcome to this video so
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in this video i will show you a python
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program which is asked in various
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placement coding examinations
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competitive exams such as gate so this
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is actually how to swap two variables
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without using the third variable so this
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is actually the program that i written
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swapping means that we need to exchange
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both the numbers or both the variables
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so you actually run the program first of
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all let me run this
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so as you run the script here you need
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to you need to be entering two numbers
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so enter the first number i write five
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enter the second number and i write
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eight so after executing this program
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now the both these numbers will be
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swapped 8 will become the first number
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five will become the second number so if
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i enter it you will see before swapping
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it was 58 after swapping it is 85 so now
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the how to do this without using the
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third variable this is actually the
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program so let me paste this program and
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show you step by step using this
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software
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pythonutor.com which will actually
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visualize the execution of the program
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step by step so first of all we are on
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this step it is asking you to enter the
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number so i will say five then it moves
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to the second step
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this variable has been registered x is
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stored inside five now we enter the y
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value which is
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10 so now both these variables have been
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assigned in global variables x is
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holding five y is holding 10 now before
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swapping you will see it is 5 10 now we
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come to the logic how we do this without
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using the third variable first of all uh
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the first step here is to calculate the
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sum of both these numbers which is 5 +
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10 so we calculate the sum the sum comes
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out to be 15 and we store this 15
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variable 15 value in the x variable so
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the first step is this x is equal to x +
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y if you do this now you will see the
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value is replaced here of x we add both
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these numbers and then store this into x
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so x is now 15 then the next step is we
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actually calculate the we subtract both
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these numbers so now x is
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15 y is 10 so 15 minus 10 comes out to
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be five and we store this value inside
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your y variable so now as we execute
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this step now y will become five
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so as you can see now y has become
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five and now in the next step we again
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need to calculate the we need to
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subtract both these numbers which is 15
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minus 5 which comes out to be
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10 so now the value 10 will be replaced
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here of
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x so in this easy way you can see both
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the numbers have been swapped and uh
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using these arithmetic operations and we
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haven't used the third variable as you
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can
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see now in the next step after swapping
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it is 10 five so just make see uh both
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these operation first of all we add both
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these numbers 10 + 5 we store it inside
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x and then we do the subtraction 15 - 10
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comes out to be five which
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we so here you can see the value is
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swapped of x it stored inside y and then
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again we calculate the subtract comes
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out to be five
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sorry 10 so we replace
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it so in this easy way
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uh you can do this so you can take any
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example for example if you take uh any
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number it can swap here also if i run
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this if i say 100 and then
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200 can see so this is a very simple
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logic very simple program ask inside
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interviews and placements how to swap
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two numbers or variables without using
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the third variable so in this way you
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can do this uh please hit that like
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button subscribe the channel and also
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check out my website freemediatools.com
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uh which contains thousands of