Decorators is a concept that belongs to the Functional Programming and you can't find this concept in procedural programming like C/C++ or Object Oriented Programming like Java, Php. Decorators allow you to use another function inside a function and you can use that function to perform different tasks without changing the original function code. Simple understand this concept as "Using Function Inside a Function" Here's a simple program in python which demonstrates the concept of decorators.
def higher_function():
def lower_function():
print("How you doing")
lower_function()
higher_function()
You can see the output as:
Now let's see the working of decorators. We would create a function that subtracts two values like if we passed (3,5) then it will return -2 as output but remember we want to subtract 3 from 5 and returns output as 2 (not negative). Then in this case we use decorators to modify existing function class that subtracts two values.
def subtraction(x,y):
print(x-y)
def sub(func):
def operation(x,y):
if x<y:
x,y=y,x
return func(x,y)
return operation
subtraction=sub(subtraction)
subtraction(5,10)
You can see the output as follows:
