Kỹ thuật lập trình hệ cơ điện tử= programming engineering in mechatronics chapter ii modular programming in c++

TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI

KỸ THUẬT LẬP TRÌNH HỆ CƠ ĐIỆN TỬ

Programming Engineering in Mechatronics
Giảng viên: TS. Nguyễn Thành Hùng
Đơn vị: Bộ môn Cơ điện tử, Viện Cơ khí

Hà Nội, 2020

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Chapter II. Modular programming in C++
• Structured programming relies on top-down design.
• In C and C++ languages, the smallest structural unit having
independent functionality is called function.
• If functions or a group of functions belonging together are
put in a separate module (source file), modular
programming is realised.

• Structural programming also contributes to creating new
programs from achieved modules (components) by bottomup design.
• This chapter aims to introduce the modular and procedural
programming in C++.
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Chapter II. Modular programming in C++
❖ The basics of functions

❖ How to use functions on a more professional level?
❖ Namespaces and storage classes
❖ Preprocessor directives of C++

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Chapter II. Modular programming in C++
❖ The basics of functions

❖ How to use functions on a more professional level?
❖ Namespaces and storage classes
❖ Preprocessor directives of C++

4


The basics of functions
❖ Defining, calling and declaring functions
❖ The return value of functions

❖ Parametrizing functions
❖ Programming with functions

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The basics of functions
• In C++, a function is a unit (a subprogram) that has a name and that can
be called from the other parts of a program as many times as it is

needed.

• In order to use a function efficiently, some of its inner variables
(parameters) are assigned a value when the function is called.
• When a function is called (activated), the values (arguments) to be
assigned to each parameter have to be passed in a similar way.

• The called function passes control back to the place where it was called
by a return statement.
• The value of the expression in the return statement is the return
value returned back by the function, which is the result of the function
call expression.

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The basics of functions
❖ Defining, calling and declaring functions
•

C++ Standard Library provides us many useful predefined
functions.
function

header file

sqrt()
isalpha()
atoi()
rand()

cmath
cctype
cstdlib
cstdlib

strlen()
wcslen()

cstring
cwchar
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The basics of functions
❖ Defining, calling and declaring functions
•

The general form of a function definition is the following (the
signs 〈 〉 indicate optional parts):

Function definition

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The basics of functions
❖ Defining, calling and declaring functions

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The basics of functions
❖ Defining, calling and declaring functions
•

The steps of calling a function
function_name (〈argument 1 , argument 2 , … argument n 〉)

Steps of calling a function
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The basics of functions
❖ Defining, calling and declaring functions
•

C++ standards require that functions have to be declared before
they are called.
Function declaration

Function definition

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The basics of functions
❖ Defining, calling and declaring functions
•

The complete declaration of a function (its prototype ):
return_value function_name(〈parameter declaration list〉);
return_value function_name(〈type_list〉);

declaration

C interpretation

C++ interpretation

type funct();

type funct(...);

type funct(void);

type funct(...);

type funct(...);

type funct(...);

type funct(void);

type funct(void);

type funct(void);

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The basics of functions
❖ Defining, calling and declaring functions
•

C++ makes it possible that a parameter list containing at least one parameter
should end with three dots (...).

•

The transferring (throw) of exceptions to the caller function can be enabled or
disabled in function header
return_type function_name (〈parameterlist〉) 〈throw(〈type_list〉)〉
{
〈local definitions and declarations〉
〈statements〉
return 〈expression〉;
}

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The basics of functions
❖ The return value of functions
•

The return_type figuring in the definition/declaration of a function
determines the return type of the function, which can be of any C++ type with
the exception of arrays and functions.

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The basics of functions
❖ The return value of functions
•

By using the type void, we can create functions that do not
return any value.

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The basics of functions
❖ The return value of functions
•

Functions can return pointers or references

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The basics of functions
❖ Parametrizing functions
•

A parameter can be scalar (bool, char, wchar_t, short, int, long, long long,
float, double, enumeration, reference and pointer) or structure, union, class
or array.
The general form of polynomials:

Horner's scheme

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The basics of functions
❖ Parametrizing functions
▪

Parameter passing methods

•

Passing parameters by value

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The basics of functions
❖ Parametrizing functions
▪

Parameter passing methods

•

Passing parameters by value

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The basics of functions
❖ Parametrizing functions
▪

Parameter passing methods

•

Passing parameters by reference

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The basics of functions
❖ Parametrizing functions
▪

Parameter passing methods

•

Passing parameters by reference

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The basics of functions
❖ Parametrizing functions
▪

Parameter passing methods

•

Passing parameters by reference

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The basics of functions
❖ Parametrizing functions
▪

Using parameters of different types

•

Arithmetic type parameters

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The basics of functions
❖ Parametrizing functions
▪

Using parameters of different types

•

Arithmetic type parameters

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The basics of functions
❖ Parametrizing functions
▪

Using parameters of different types

•

User-defined type parameters

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