There are 3 things going on with your script.
1. a is global variable assigned the value of 10.
2. You function is a function that has a default value set. that is global a which got the value of 10.
due to that
will print the default value which is
because a=10. So when you call
it will return the default value.
Try and call foo(a) on line 6. This will print the current value of a which is 5.
3.Variable scope and function definations are very simple once you master them.
As you can see.
took no value. As long as you dont give a value to
.... It will keep printing the value of first a which is 10.