In this post, we will see programs for how to print even natural number upto n in python, provided n is positive.

Even Number : Any integer either positive or negative, which can be divided exactly by 2 is an even number.The numbers having last digit is 0, 2, 4, 6 or 8 are considered as an even number.

Note : Natural number is positive integers. It’s range from 1 to infinity.

Examples:

Input:     n : 10

Output:    2   4   6   8   10

Input:     n : 15

Output:    2   4   6   8   10   12   14

Let’s see the different version of codes for this program :

Code version 1: Using a concept of range() function with for loop.

# main code
if __name__ == "__main__" :

    # input value of n
    n = 10

    # for loop starts from 2
    # and ends on n-2.
    # each time value of variable  
    # i is incremented by 2
    for i in range(2,n,2) :
        
        # print value of variable i
        # and end parameter is space
        # so print all outputs
        # in a single line
        print(i,end=" ")

Output: 2 4 6 8

Code version 2: Using a concept of pass statement with for loop.

 

# main code
if __name__ == "__main__" :

    # input value of n
    n = 15

    # for loop starts from 1
    # and ends on n-1.
    # each time value of variable  
    # i is incremented by 1
    for i in range(1,n) :
        # 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 variable i
            # and end parameter is space
            # so print all outputs
            # in a single line
            print(i,end=" ")

Output: 2 4 6 8 10 12 14

Code version 3: Using a concept of continue statement with for loop.

# main code
if __name__ == "__main__" :

    # input value of n
    n = 20

    # for loop starts from 1
    # and ends on n-1.
    # each time value of variable  
    # i is incremented by 1
    for i in range(1,n) :

        # if condition is True
        # that means i % 2 gives
        # non-zero value then
        # just go to next iteration
        # else print i
        if i % 2 :
            continue

        # if condition is false
        # that means i % 2 return 0
        else :
            
            # print value of variable i
            # and end parameter is space
            # so print all outputs
            # in a single line
            print(i,end=" ")

Output: 2 4 6 8 10 12 14 16 18

Code version 4: Using a concept of increment operator with while loop .

# main code
if __name__ == "__main__" :

    # input value of n
    n = 20

    # initialise value of i by 2
    i = 2
    
    # while loop starts from 1
    # run untill value of i
    # is less than n  
    while i < n :
        
        # print value of variable i
        # and end parameter is space
        # so print all outputs
        # in a single line
        print(i,end=" ")

        # each time value of variable  
        # i is incremented by 2
        i += 2

Output: 2 4 6 8 10 12 14 16 18

Code version 5: Using a concept of pass statement with while loop .

# main code
if __name__ == "__main__" :

    # input value of n
    n = 20

    # initialise value of i by 1
    i = 1
    
    # while loop starts from 1
    # run untill value of i
    # is less than n  
    while i < n :

        # 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 variable i
            # and end parameter is space
            # so print all outputs
            # in a single line
            print(i,end=" ")

        # each time value of variable  
        # i is incremented by 1
        i += 1

Output: 2 4 6 8 10 12 14 16 18