Can someone explain me this code?

It's Python - you have to be careful about the white-space indentations (below, each indent is a tab, but you can use spaces - but don't mix them!):

def fact_iterative(n):
	fact=1
	for i in range(n):
		fact=fact *(i+1)
	return fact

n=int(input("enter:"))

print("ITERATIVE FACTORIAL:",fact_iterative(n))

once you get that right it works correctly.
Also if you're copy-pasting or typing this into a python interpreter, each chunk needs to be entered separately.

Quote:

can you explain me how this code works?

You are kidding, right?
The code is trivial: it declares a function (called fact_iterative) that takes a parameter value and returns it's factorial.
It then gets a value from the user, calls the function (passing the value) and prints the returned value.

The body of the function is a trivial loop!

TBH, if you can't work that out for yourself, then you need to go back to the start of your course, and read all the way though - there is nothing complicated going on here at all!

Quote:

Can someone explain me this code?

Rather than a magic explanation, watch the code perform.
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Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your code is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]

27.3. pdb — The Python Debugger — Python 3.6.1 documentation[^]
Debugging in Python | Python Conquers The Universe[^]
pdb – Interactive Debugger - Python Module of the Week[^]

The debugger is here to only show you what your code is doing and your task is to compare with what it should do.