Giáo trình tin học chương 3

3.2 Program Components in C++• Modules: functions and classes• Programs use new and “prepackaged” modules– New: programmer-defined functions, classes– Prepackaged: from the standard library • Functions invoked by function call– Function name and information (arguments) it needs• Function definitions– Only written once– Hidden from other functions
Nội dung trích xuất từ tài liệu:
Giáo trình tin học chương 3 1 Chapter 3 - Functions Outline 3.1 Introduction 3.2 Program Components in C++ 3.3 Math Library Functions 3.4 Functions 3.5 Function Definitions 3.6 Function Prototypes 3.7 Header Files 3.8 Random Number Generation 3.9 Example: A Game of Chance and Introducing enum 3.10 Storage Classes 3.11 Scope Rules 3.12 Recursion 3.13 Example Using Recursion: The Fibonacci Series 3.14 Recursion vs. Iteration 3.15 Functions with Empty Parameter Lists 2003 Prentice Hall, Inc. All rights reserved. 2 Chapter 3 - Functions Outline 3.16 Inline Functions 3.17 References and Reference Parameters 3.18 Default Arguments 3.19 Unary Scope Resolution Operator 3.20 Function Overloading 3.21 Function Templates 2003 Prentice Hall, Inc. All rights reserved. 3 3.1 Introduction • Divide and conquer – Construct a program from smaller pieces or components – Each piece more manageable than the original program 2003 Prentice Hall, Inc. All rights reserved. 4 3.2 Program Components in C++ • Modules: functions and classes • Programs use new and “prepackaged” modules – New: programmer-defined functions, classes – Prepackaged: from the standard library • Functions invoked by function call – Function name and information (arguments) it needs • Function definitions – Only written once – Hidden from other functions 2003 Prentice Hall, Inc. All rights reserved. 5 3.3 Math Library Functions • Perform common mathematical calculations – Include the header file • Functions called by writing – functionName(argument1, argument2, …); • Example cout 6 3.3 Math Library Functions • Function arguments can be – Constants • sqrt( 4 ); – Variables • sqrt( x ); – Expressions • sqrt( sqrt( x ) ) ; • sqrt( 3 - 6x ); 2003 Prentice Hall, Inc. All rights reserved. 7 M e th o d D e sc rip t io n Exa m p le ceil( x ) ro u n d s x to th e sm a lle st in te g e r c e i l ( 9 . 2 ) is 1 0 . 0 n o t le ss th a n x c e i l ( - 9 . 8 ) is - 9 . 0 cos( x ) trig o n o m e tric c o sin e o f x c o s ( 0 . 0 ) is 1 . 0 (x in ra d ia n s ) exp( x ) e x p o n e n tia l fu n c tio n e x e x p ( 1 . 0 ) is 2 . 7 1 8 2 8 e x p ( 2 . 0 ) is 7 . 3 8 9 0 6 fabs( x ) a b so lu te v a lu e o f x f a b s ( 5 . 1 ) is 5 . 1 f a b s ( 0 . 0 ) is 0 . 0 f a b s ( - 8 . 7 6 ) is 8 . 7 6 floor( x ) ro u n d s x to th e la rg e st in te g e r f l o o r ( 9 . 2 ) is 9 . 0 n o t g re a te r th a n x f l o o r ( - 9 . 8 ) is - 1 0 . 0 fmod( x, y ) re m a in d e r o f x /y a s a flo a tin g - f m o d ( 1 3 . 6 5 7 , 2 . 3 3 3 ) is 1 . 9 9 2 p o in t n u m b e r log( x ) n a tu ra l lo g a rith m o f x (b a se e ) l o g ( 2 . 7 1 8 2 8 2 ) is 1 . 0 l o g ( 7 . 3 8 9 0 5 6 ) is 2 . 0 log10( x ) lo g a rith m o f x (b a s e 1 0 ) ...