the code above is correct, cause I changed the line 3 into "n = len(text) - 1" and line 4 into "while n > -1".

The question is what if I delete both of "-1" in these two lines? I mean, line 3: "n = len(text)", line 4: "while n > 0", Because I think it is equal to the correct one. I tried this one, it cannot work out, but I don't know why.

I want to know why the change I thought can not equal to the correct one? and why should "n = len(text)" subtract 1?

thanks for your answering and time!

```
def reverse(text):
result = []
n = len(text) - 1
while n > -1:
result.append(text[n])
n = n - 1
return ("".join(result))
```