The definition of a function specifies exactly how a function is constructed, what parameters are passed to it, and what value it returns to the calling function.
With the declaration we name a variable and make it known to the compiler.
Definition and declaration differ in some points. The definition includes a memory allocation for the function, while no memory is allocated in the declaration. The declaration can be done several times, vice versa a function can be defined exactly once in a program.
In Python, functions are defined with the keyword def
followed by the function name and the input parameters.
def function_name():
# code to be executed
def function_name(parameter_1 = default_value, parameter_2 = default_value, ...):
# code to be executed
def add():
# code to be executed
Line | Description |
---|---|
1 | Defines the function add() with the input parameters a and b . Variable a is assigned the value 3 in the function header and variable b the value 5 |
2 | The function returns the sum of a and b |
def add(a = 3, b = 5):
return a + b