Answer:
in python:
n = int ( input ( "Pick a number" ) )
total = 0
for num in range ( 0, n+1, 2 ) :
total = total + num
print ( total )
Step-by-step explanation
this algorithm will calculate the sum of all even number from 0 till the number that was inputed by the user. *the reason why there is an n+1 is because in python, the number entered will not be counted. for example if there is an input of 25, this will calculate the sum of even integers from 0 to 24. so we add 1 which will get 26. so if there is an input of 25, the code will solve it from 0 to 25.