In this post, we will see how to print first n even natural numbers in python?
Even Numbers:
Any integer that is positive or negative which can be divided exactly by 2 is an even number. The numbers having the last digit is 0, 2, 4, 6 or 8 are even numbers.
Note : Natural number is positive integers. It’s range from 1 to infinity.
Examples:
Input:Â Â Â Â Â n: 5
Output:Â Â 5 first even numbers are: 2 4 6 8 10
Input:Â Â Â n: 6
Output:Â 6 first even numbers are: 2Â Â 4Â Â 6Â Â 8Â Â 10Â Â 12
Let’s see the different version of codes for this program :
Code version 1: Using a counter.
In this code, we take a counter variable ‘even’ initialized by 2 and on every iteration, this counter value is incremented by 2.
# main code if __name__ == "__main__" : # input value of n n = 11 # take a even variable # and assign 2 to it even = 2 print("even numbers are: ") # loop run from 0 # to n - 1 for i in range(n) : # print value of even variable # and end parameter is ',' # so print all outputs # in a single line with ',' print(even,end = ",") # increment by 2 # in every iteration even += 2
Output: even numbers are: 2,4,6,8,10,12,14,16,18,20,22,
Code version 2: Using an if-else statement along with for loop.
In this code, we run a loop from 2 to 2 * n, and in every iteration, we check the value of i is divisible by 2 or not if divisible then it is even otherwise odd.
# main code if __name__ == "__main__" : # input value of n n = 7 print("even numbers are: ") # loop run from 2 # to 2 * n for i in range(2, 2 * n + 1) : # if condition is True # that means i % 2 gives # non-zero value then # just ignore this block # else print i if i % 2 : pass # if condition is false # that means i % 2 return 0 else : # print value of i variable # and end parameter is ',' # so print all outputs # in a single line with ',' print(i, end = ",")
Output: even numbers are: 2,4,6,8,10,12,14,
Note : Code version 1 and 2 can also be written using While loop.
Code version 3: Using a range() function concept.
As we know, we can pass 3 parameters in range() function, the third parameter is stepped i.e jump after each iteration.
# main code if __name__ == "__main__" : # input value of n n = 7 print("even numbers are: ") # loop run from 2 # to 2 * n for even in range(2, 2 * n + 1, 2) : # print value of even variable # and end parameter is ',' # so print all outputs # in a single line with ',' print(even, end = ",")
Output: even numbers are: 2,4,6,8,10,12,14,