Following code intends to add a given value to global variable a. def increase(x): #1 a = a + x #2

Q. Following code intends to add a given value to global variable a. What will the following code produce ?

def increase(x): #1

    a = a + x #2

    return #3

#4

a = 20 #5

b = 5 #6

increase(b) #7

print(a) #8

Answer :-

The above code will produce an error.

The reason being whenever we assign something to a variable inside a function, the variable is created as a local variable. Assignment creates a variable in Python.

Thus in line 2, when variable a is incremented with the passed value x, Python tries to create a local variable a by assigning to it the value of the expression on the right-hand side of the assignment. But variable a also appears on the right-hand side of the assignment, which results in an error because a is undeclared so far in function.

To assign some value to a global variable from within a function, without creating a local variable with the same name, the global statement can be used. So, if we add

global a

In the first line of the function body, the above error will be corrected. Python won't create a local variable a, rather will work with global variable a.