Page 205 - Computer Science V2.0 Class 11

A function is a sub-program that manipulates data received as an input to solve a problem or sub-problem of a complex
problem and often returns one or more results. Once a function has been defined, it may be called several times from
different parts of the program. Subsequently, the functions are integrated to solve the complex problem.

The programming methodology that focuses on organising a computer program into smaller manageable
sub-programs or modules is called modular programming.

8.1 Built-in Functions

Python provides a large number of pre-defined built-in functions such as input(), print(), and abs().
Some commonly used types of built-in functions are related to input-output, data type conversion, and mathematical
operations. A function is invoked using the function's name followed by the sequence of arguments (separated by
commas) within a pair of matching parentheses. The function arguments serve as inputs to the function for performing
its computations. Some commonly used types of built-in functions are mentioned below:

Input-Output Data Type Conversion
Functions Functions

input() int()
print() chr()
dict()
float()

Built-In Functions

Mathematical Other
Functions Functions
abs()
max() len()
min() id()
sum() type()
range()
pow()
Some commonly used built-in functions

8.1.1 Commonly used Built-in Functions

print()
As the computer screen is the default device for displaying the results, the output produced on invoking the print()
function is displayed on the screen.

>>> print('Hello')
Hello
In the above example, 'Hello' is the argument passed to the function print(). The print() function may be
invoked with an arbitrary number of arguments. For example, the following function call makes use of two arguments:

>>> print('Hello!', 'How are you?')
Hello! How are you?
Next, we make use of print() function for displaying the value of an arithmetic expression,
>>> print(2+14)
16

Introduction to Functions 191