程式設(shè)計(jì)簡(jiǎn)介課件

1、程式設(shè)計(jì)簡(jiǎn)介李俊宏2006/11/03程式設(shè)計(jì)簡(jiǎn)介李俊宏何謂程式與程式設(shè)計(jì)程式控制電腦如何做動(dòng)作的指令集合程式設(shè)計(jì)設(shè)計(jì)一組指令集合控制電腦做動(dòng)作何謂程式與程式設(shè)計(jì)程式控制電腦如何做動(dòng)作的指令集合程式設(shè)計(jì)設(shè)何謂電腦系統(tǒng)以及為何要作程式設(shè)計(jì)作業(yè)系統(tǒng)使用者使用者使用者程式設(shè)計(jì)師程式編譯軟體組合語言編譯軟體文字編輯軟體資料庫系統(tǒng)軟體電腦硬體電腦軟體Office 軟體黃易群俠傳遊戲軟體系統(tǒng)軟體何謂電腦系統(tǒng)以及為何要作程式設(shè)計(jì)作業(yè)系統(tǒng)使用者使用者使用者程由硬體觀點(diǎn)看程式設(shè)計(jì)計(jì)算邏輯單元控制單元暫存器主記憶體輸入輸出硬碟控制器外接硬體界面CPU電腦程式由硬體觀點(diǎn)看程式設(shè)計(jì)計(jì)算邏輯單元控制單元暫存器主記憶體輸

2、入輸程式語言, 程式, c+之間的關(guān)係為何程式控制電腦如何做動(dòng)作的指令集合程式語言寫指令集合時(shí)須符合的格式C+ 語言一種程式語言程式語言, 程式, c+之間的關(guān)係為何程式控制電腦如何做動(dòng)機(jī)器語言, 組合語言, 與高階語言三種程式語言(依與硬體相關(guān)性分類)機(jī)器語言 控制機(jī)器的特定數(shù)字字串-人類很難看懂例子:+1300042774+1400593419+1200274027組合語言比較像文字的控制機(jī)器的指令須組譯器轉(zhuǎn)成機(jī)器可以看懂的機(jī)器語言例子:LOAD BASEPAYADD OVERPAYSTORE GROSSPAY高階語言更像文字(英文)的控制機(jī)器的指令用數(shù)學(xué)符號(hào)來表示運(yùn)算式例子grossPa

3、y = basePay + overTimePay1/* Fig. 2.1: fig02_01.c2 A first program in C */3#include 45int main()67 printf( Welcome to C!n );89 return 0;10 機(jī)器語言, 組合語言, 與高階語言三種程式語言(依與硬體相關(guān)基礎(chǔ)的程式發(fā)展環(huán)境基礎(chǔ)的程式發(fā)展步驟編輯前置處理編譯連結(jié)載入執(zhí)行 編輯程式處理程式的前置碼載入主記憶體CPU按順序一個(gè)一個(gè)執(zhí)行被轉(zhuǎn)成機(jī)器語言的程式碼編譯程式轉(zhuǎn)成機(jī)器語言並存到儲(chǔ)存裝置連結(jié)外部的函式庫(別人寫好的)載入器主記憶體編譯器編輯器前置處理器連結(jié)器主記憶體

4、.DiskDisk磁碟CPUDiskDiskIDE(整合開發(fā)環(huán)境)基礎(chǔ)的程式發(fā)展環(huán)境基礎(chǔ)的程式發(fā)展步驟編輯程式處理程式的前程式的整體觀點(diǎn)電腦系統(tǒng)使用者其他系統(tǒng)ControlInterfaceData硬體觀點(diǎn)輸出入裝置CPU儲(chǔ)存裝置視窗畫面程式執(zhí)行的控制資料結(jié)構(gòu)軟體觀點(diǎn)程式的整體觀點(diǎn)電腦系統(tǒng)使用者其他系統(tǒng)ControlInter程式例子1/* Fig. 2.1: fig02_01.c2 A first program in C+ */3#include 44using std:cout;5int main()67 cout“我是李俊宏”;89 return 0;10 程式例子1/* Fig. 2

5、.1: fig02_01.c三大程式基本要素#include int main() int row = 10, column; while ( row = 1 ) column = 1; while ( column = 10 ) printf( %s, row % 2 ? ); +column; -row; printf( n ); return 0;資料控制流程動(dòng)作三大程式基本要素#include 資料控制資料: Variable (變 數(shù))#include main() int a, b;a = 1;b = a + 2;printf(The value of 1+2 is %i., b)

6、;031ab? ? ? ? ? ? ?0000 0000 0000 00010000 0000 0000 0011The value of 1+2 is 3.電腦記憶體 RAM資料: Variable (變 數(shù))#include = 60 ) printf( Passedn ); truefalsegrade = 60print “Passed”The if Selection StructurePseuThe if/else Selection StructureC code:if ( grade = 60 ) printf( Passedn);else printf( Failedn);

7、truefalseprint “Failed”print “Passed”grade = 60The if/else Selection StructurThe while Repetition StructureExample: int product = 2;while ( product = 1000 )product = 2 * product;product = 1000product = 2 * producttruefalseThe while Repetition StructureThe for Repetition Structure格式for (初值; 狀況測(cè)試; 增加

8、) 要重覆的內(nèi)容 Example: for( int counter = 1; counter = 10; counter+ ) printf( %dn, counter );印出整數(shù) 1 - 10No semicolon (;) after last expressioncounter=10printf( %dn, counter )truefalseint counter=1The for Repetition Structure格式The switch Multiple-Selection Structure格式switch ( value )case 1:動(dòng)作break;case 2:

9、動(dòng)作break;default:動(dòng)作break;break; 離開的點(diǎn)The switch Multiple-Selection switch 多重選擇結(jié)構(gòu)Flowchart of the switch structuretruefalse.case acase a action(s)breakcase bcase b action(s)breakfalsefalsecase zcase z action(s)breaktruetruedefault action(s)switch 多重選擇結(jié)構(gòu)Flowchart of the do/while 重覆結(jié)構(gòu)Example (counter = 1

10、):do printf( %d , counter ); while (+counter = 10);Prints the integers from 1 to 10truefalse動(dòng)作(s)條件do/while 重覆結(jié)構(gòu)Example (counter 動(dòng)作功能函數(shù)結(jié)構(gòu)化程式設(shè)計(jì)動(dòng)作功能函數(shù)結(jié)構(gòu)化程式設(shè)計(jì)介紹.Rule 2Rule 2Rule 2規(guī)則 1 由最簡(jiǎn)單的流程圖開始規(guī)則 2 任意一個(gè)程序方塊可以被分解成二個(gè)連續(xù)的小程序方塊結(jié)構(gòu)化程式設(shè)計(jì)介紹.Rule 2Rule 2Rule 2規(guī)則結(jié)構(gòu)化程式設(shè)計(jì)介紹Rule 3Rule 3Rule 3規(guī)則 3 將任意一個(gè)程序方塊用控制結(jié)構(gòu)來取代結(jié)

11、構(gòu)化程式設(shè)計(jì)介紹Rule 3Rule 3Rule 3規(guī)則 結(jié)構(gòu)化程式設(shè)計(jì)的目標(biāo)分解並各個(gè)擊破 由小程序方塊或元件開始建構(gòu)一個(gè)程式這些小程序方塊叫作程式模組程式模組比單一的程式更好管理結(jié)構(gòu)化程式設(shè)計(jì)的目標(biāo)分解並各個(gè)擊破 在 C 語言中的程式模組FunctionsModules in CPrograms combine user-defined functions with library functionsC standard library has a wide variety of functionsFunction callsInvoking functionsProvide functi

12、on name and arguments (data)Function performs operations or manipulationsFunction returns resultsFunction call analogy:Boss asks worker to complete taskWorker gets information, does task, returns resultInformation hiding: boss does not know details在 C 語言中的程式模組FunctionsMath Library FunctionsMath libr

13、ary functions perform common mathematical calculations#include Format for calling functionsFunctionName( argument );If multiple arguments, use comma-separated listprintf( %.2f, sqrt( 900.0 ) ); Calls function sqrt, which returns the square root of its argumentAll math functions return data type doub

14、leArguments may be constants, variables, or expressionsSome math library function examplesfabs(x) absolute value of x fabs(-5.0) is 5.0pow(x, y) power pow(2,7) is 128refer to p.146 fig. 5.2 .More informationMath Library FunctionsMath lib1/* Fig. 5.4: fig05_04.c2 Finding the maximum of three integers

15、 */3#include 45int maximum( int, int, int ); /* function prototype */67int main()89 int a, b, c;1011 printf( Enter three integers: );12 scanf( %d%d%d, &a, &b, &c );13 printf( Maximum is: %dn, maximum( a, b, c ) );1415 return 0;161718/* Function maximum definition */19int maximum( int x, int y, int z

16、 )2021 int max = x;2223 if ( y max )24 max = y;2526 if ( z max )27 max = z;2829 return max;30Function prototype(3 parameters)2. Input values2.1 Call functionFunction definition1/* Fig. 5.4: fig05_04.c2 FunctionsFunctionsModularize a programAll variables declared inside functions are local variablesK

17、nown only in function definedParametersCommunicate information between functionsLocal variablesBenefits of functionsDivide and conquerManageable program developmentSoftware reusabilityUse existing functions as building blocks for new programsAbstraction - hide internal details (library functions)Avo

18、id code repetitionFunctionsFunctionsFunction DefinitionsFunction definition format (continued)return-value-type function-name( parameter-list ) declarations and statements Declarations and statements: function body (block)Variables can be declared inside blocks (can be nested)Functions can not be defined inside other functionsReturning controlIf nothing returned return; or, until reaches right braceIf something returned return expression;Function DefinitionsFunction dFunction PrototypesFunction prototype Function nameParameters