# Giáo trình tin học chương 2

Chia sẻ: Minh Tuan | Ngày: | Loại File: PDF | Số trang:60

0
293
lượt xem
59

## Giáo trình tin học chương 2

Mô tả tài liệu

Control Structures • Sequential execution – Statements executed in order • Transfer of control – Next statement executed not next one in sequence • 3 control structures (Bohm and Jacopini) – Sequence structure • Programs executed sequentially by default – Selection structures • if, if/else, switch – Repetition structures • while, do/while, for

Chủ đề:

Bình luận(0)

Lưu

## Nội dung Text: Giáo trình tin học chương 2

1. 1 Chapter 2 - Control Structures Outline Control Structures if Selection Structure if/else Selection Structure while Repetition Structure Formulating Algorithms: Case Study 1 (Counter-Controlled Repetition) Formulating Algorithms with Top-Down, Stepwise Refinement: Case Study 2 (Sentinel-Controlled Repetition) Formulating Algorithms with Top-Down, Stepwise Refinement: Case Study 3 (Nested Control Structures) Assignment Operators Increment and Decrement Operators Essentials of Counter-Controlled Repetition for Repetition Structure switch Multiple-Selection Structure do/while Repetition Structure break and continue Statements Logical Operators Confusing Equality (==) and Assignment (=) Operators Structured-Programming Summary  2003 Prentice Hall, Inc. All rights reserved.
2. 2 Control Structures • Sequential execution – Statements executed in order • Transfer of control – Next statement executed not next one in sequence • 3 control structures (Bohm and Jacopini) – Sequence structure • Programs executed sequentially by default – Selection structures • if, if/else, switch – Repetition structures • while, do/while, for  2003 Prentice Hall, Inc. All rights reserved.
3. 3 Control Structures • C++ keywords – Cannot be used as identifiers or variable names C++ Keyw o rd s Keywords common to the C and C++ programming languages auto break case char const continue default do double else enum extern float for goto if int long register return short signed sizeof static struct switch typedef union unsigned void volatile while C++ only keywords asm bool catch class const_cast delete dynamic_cast explicit false friend inline mutable namespace new operator private protected public reinterpret_cast static_cast template this throw true try typeid typename using virtual wchar_t  2003 Prentice Hall, Inc. All rights reserved.
4. 4 if Selection Structure • in C++ If student’s grade is greater than or equal to 60 Print “Passed” if ( grade >= 60 ) cout = 60 print “Passed” nonzero - true Example: false 3 - 4 is true  2003 Prentice Hall, Inc. All rights reserved.
5. 5 if/else Selection Structure • if – Performs action if condition true • if/else – Different actions if conditions true or false • Pseudocode if student’s grade is greater than or equal to 60 print “Passed” else print “Failed” • C++ code if ( grade >= 60 ) cout
6. 6 if/else Selection Structure • Ternary conditional operator (?:) – Three arguments (condition, value if true, value if false) • Code could be written: cout = 60 ? “Passed” : “Failed” ); Condition Value if true Value if false false true grade >= 60 print “Failed” print “Passed”  2003 Prentice Hall, Inc. All rights reserved.
7. 7 Nested if/else structures • Example if ( grade >= 90 ) // 90 and above cout = 80 ) // 80-89 cout = 70 ) // 70-79 cout = 60 ) // 60-69 cout
8. 8 if/else Selection Structure • Compound statement – Set of statements within a pair of braces if ( grade >= 60 ) cout
9. 9 while Repetition Structure • Example int product = 2; while ( product
10. 10 Formulating Algorithms (Counter-Controlled Repetition) • Counter-controlled repetition – Loop repeated until counter reaches certain value • Definite repetition – Number of repetitions known • Example A class of ten students took a quiz. The grades (integers in the range 0 to 100) for this quiz are available to you. Determine the class average on the quiz.  2003 Prentice Hall, Inc. All rights reserved.