En kucuk calisabilir birime satetement denir Statements semicolon (;) ile sonlanir Yalniz basina ; null statement i ifade eder

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1 C++ Statements C++ control structures En kucuk calisabilir birime satetement denir Statements semicolon (;) ile sonlanir Yalniz basina ; null statement i ifade eder Ornek: while (*str++ = *inbuf++) ; { ve arasinda ifade edilen bir dizi statement bir compound statement olusturur. Compound statement in ; ile sonlanma zorunlulugu yok (fakat sonlanirsa bu hata degil) Nesneye Yonelik Programlama 2.1 Control structures program control akisini kosula bagli olarak degistirir goto unconditional jump if eger kosul dogruysa if in statement ini run et. if-else two-way branch on condition while while kosulu dogru oldugu surece tekrarla for counter-controlled repetition do-while kosul dogruysa tekrarla (en az bir kere) switch multi-way branch Nesneye Yonelik Programlama 2.2 goto statement Unconditional jump goto <statement label> Ornek: count = count + 1; goto exitpoint; exitpoint: return 0; Nesneye Yonelik Programlama 2.3 Nesneye Yonelik Programlama 2.4

2 Structured programming Structured programming, programlama disiplinidir sadece high-level (yuksek) seviyeli control structure lari kullanilir goto statement I kullanilmaktan kacinilir Boehm ve Jacopini, sadece if-else ve dowhile yapilari kullanilarak programlama yapilabilecegini gosterdi. Nesneye Yonelik Programlama 2.5 if control structure if (grade >= 60) cout << Passed ; if(x>y) { Nesneye Yonelik Programlama 2.6 if-else control structure if (<expression>) else <if-statement> <else-statement> if (grade >= 60) cout << Passed ; Else cout << Failed ; if-else Nesneye Yonelik Programlama 2.7 Nesneye Yonelik Programlama 2.8

3 Conditional (?:) Operator C++ daki tek ternary operator if-else control structure i ile ilgili (<expr>? <True-statmt >:<False-statmt >) Ornek: cout<< (grade >= 60? Passed : Failed ); Daha once verilen if-else ornegi ile ayni Nesneye Yonelik Programlama 2.9 Nesneye Yonelik Programlama 2.10 while control structure ornekler int product = 2; while (<expression>) statement Nesneye Yonelik Programlama 2.11 while (product <=1000) product = 2 * product; int dummy; while (true) { // end while cin >> dummy; cout << dummy * 2 << endl Nesneye Yonelik Programlama 2.12

4 C++ daki Assignment Operators Syntax Ornek Anlami += c += 7; c = c + 7; -= d -= 4; d = d 4; *= e *= 5 e = e * 5; /= f /= 3 f = f / 3; %= g %= 9 g = g % 9; Increment ++ ve Decrement -- Operators Ornek Isim Anlami ++a Preincrement a yi 1 artir ve a nin degerini expression da kullan b++ Postincrement b nin degerini expressda kullan ve sonra b yi 1 artir --c d-- Predecrement Postdecrement Nesneye Yonelik Programlama 2.13 Nesneye Yonelik Programlama 2.14 for control structure Syntax: for ( <expr1>; <expr2>; <expr3>) <statement> <expr1> baslangic degeri atanmasi (initialization) <expr2> loop surekliligi kosulu <expr3> control variable nin degisimi Semantics: <expr1> while ( <expr2>) { <statement> <expr3> Nesneye Yonelik Programlama 2.15 for control structure Ornek: int count; for (count=1; count <= 10; count++) cout << count <<endl; Ornek: for (int i=1; i<=100; i++) for (int i=100; i>=1; i--) for (int i=7; i<=77; i+=7) for (int j=99; j>=0; j-=11) Nesneye Yonelik Programlama 2.16

5 do do-while control structure <statement> while ( <expression>) do-while # include <iostream> using namespace std; int main( ) { int counter = 1; do { cout << counter << ; cout << endl; return 0; Nesneye Yonelik Programlama 2.17 Nesneye Yonelik Programlama 2.18 continue statement break statement En yakin while, do veya for loop un aktif iteration in sonlanmasina sebep olur while ve do loop lar execution loop kontrol expression la devam eder. for loop icin execution <expr2> le devam eder while (cin >> integer) { if (integer >= 100) continue // process number under 100 // process the non-five value of x cout << x << ; // end while // end for Nesneye Yonelik Programlama 2.20 Nesneye Yonelik Programlama 2.19 En yakin while, do, for, veya switch statement ini sonlandirir Program akisi sonlanan statement dan sonra gelen statement ile devam eder for (int x=1; x <=10; x++) { if (x == 5) break;

6 switch control structure switch ( <expression> ) { case <value_1>: <statement_1> break; case <value_2>: <statement_2> break; case <value_3>: <statement_3> break; default: <default_statement> break; ; // en switch Nesneye Yonelik Programlama 2.21 Nesneye Yonelik Programlama 2.22 Logical Operators Kosula bagli control structures kosula bagli olarak program akisinin nereden devam etmesi gerektigine karar verirler. C++ da 3 tane logical operator vardir Ornek Isim Precedence! expr1 Logical Negation High expr2 && expr3 Logical AND Medium expr4 expr5 Logical OR Low Nesneye Yonelik Programlama 2.23 Nesneye Yonelik Programlama 2.24

7 !, &&, ve Logical Expression ornekleri!expr1 Eger expr1 false ise,!expr1 true degerini alir expr2 && expr3 Eger expr2 ve expr3 nin her ikisi de true ise, expr2 && expr3 true olur. Aksi halde false expr4 expr5 Eger expr4 ve expr5 den en azindan biri true ise expr4 expr5 true degeri alir. Aksi halde false false! true && false! ( true && false) true false && true false true && false false (false true) && (false true) true true false true Nesneye Yonelik Programlama 2.25 Nesneye Yonelik Programlama 2.26 Comma Operator (,) C++ da Data Abstraction Comma operator birden fazla expression i birlestirmek icin kullanilir, ile birbirine baglanmis expression lara comma expression denir. Comma expression daki expression lar soldan saga dogru islem gorurler. En sagdaki expression in degeri comma expression in degerine esittir Ornek: b = (a=2, a=5, a+2 ); for (i=1, j=20; I<= 19, j-- ) Nesneye Yonelik Programlama 2.27 Bilgisayarlar hardware destekli, uzerlerinde dogrudan islem yapilabilen bir kac tip native data types sahiptir Bits, bytes, words, long words Integers, booleans, floating point, BCD Diger veri tipleri bu native data types larindan yararlanarak temsil edilirler (data abstraction kavrami) Derived data types (arrays, pointers, structures, classes, ), data abstraction destegi ile olusturulurlar. Nesneye Yonelik Programlama 2.28

8 Nesneye Yonelik Programlama 2.29 Nesneye Yonelik Programlama 2.30 Type Declaration int i, j, k; int i=5, j=7; bool alarm_status = false; char ch1= a, ch2= b ; float sample_mass; const double pi= int main( ); float f ( int ); void g (int, float ); Nesneye Yonelik Programlama 2.31 Integral data bool Arithmetic Data types unsigned (char, short, int, long) enumeration (user-defined) signed (char, short, int, long) Floating point data float double long double Nesneye Yonelik Programlama 2.32

9 Boolean Type (bool) Tipi boolean olan bir data, iki degerden birini alablir: true veya false integer lar boolean a donusturulmeleri halinde (ornegin, bir control structure indaki arithmetic expression) 0 false nonzero integer lar true ya donusturulur Character type (char) char tipi variable lar character kodlarini tutarlar Character kodlari letter (upper and lower case), digits, punctuation, symbols, control actions (ornrgin, line-feed, sound the bell), format (ornegin, tab, end-of-text) temsil ederler ASCII 128 taneden olusan 7 bitlik character kodlarini duzenler Nesneye Yonelik Programlama 2.33 Nesneye Yonelik Programlama 2.34 #include <iostream.h> int main ( ) { char c; cin >> c; cout << The value of << c << is << int (c) << endl; signed ve unsigned char Bilgisayarlar character ler icin 8 bit (1 byte) kullanirlar char 0,, 127 degerleri garanti. Bu araligin disindaki degerler bilgisayarin dizaynina bagli unsigned char 0,, 255 signed char -127,., 127 Nesneye Yonelik Programlama 2.35 Nesneye Yonelik Programlama 2.36

10 char c = a ; char digit = 4 ; Character constants char newline = \n ; char tab = \t ; Nesneye Yonelik Programlama 2.37 Integer types 3 degisik sekli: int, signed int, unsigned int int - isaretli tamsayi unsigned int - isaretsiz tamsayi (positive) signed int - int le esanlamli signed - signed int le esanlamli unsigned - unsigned int le es anlamli 3 degisik boylu: short int, int, long int short int - at az 16 bit boyunda int - 32 bit olabilir long int - en az 32 bit boyunda short - short int le es anlamli long - long int le es anlamli Nesneye Yonelik Programlama 2.38 Integer constants Decimal Octal Hexadecimal x x x3f x53 L, long int i gosterir 34L U, unsigned int I gosterir 43U Nesneye Yonelik Programlama 2.39 Floating-point types C++ 3 tip floating point data type ina sahip float - single precision double - double precision long double - extended precision Floating point constants 1.23, 0.23, 1.2e10, 1.23e-13 Default olarak bu sabitlerin tipi double dir Float constant lar f veya F ile belirlenir 2.05f, F Nesneye Yonelik Programlama 2.40

11 Static_cast Evaluation sirasinda bir variable nin type nin degistirilmesi islemi C de casting daha guclu, fakat tehlikeli Nesneye Yonelik Programlama 2.41 // Example of static_cast use #include <iostream> #include <iomanip> Using namespace std; int main ( ) { int total = 0, gradecounter = 0, grade; float average = 0.0 cout << Enter grade, -1 to end ; cin >> grade; while ( grade!= -1 ) { total += grade; gradecounter++; cin >> grade; if ( gradecounter!= 0) { average = static_cast<float>(total) / gradecounter; cout << Class average is << setprecision(2) << setioflags (ios::fixed ios::showpoint) << average <<endl; else cout << No grades were entered << endl; return 0; Nesneye Yonelik Programlama 2.42 Bir type in bellekte kapladigi alani (size) ini belirlemek Bazen belli bir tipteki verinin bellekte kapladigi alani belirlemek gerekli olur C++, bir degiskenin bellekte kapladigi alani bir character in bellekte kapladigi alan cinsinden verebilir. C++ sizeof operatore sahip. sizeof(char ) = 1 sizeof(char ) <= sizeof (short ) <= sizeof ( int ) <= sizeof (long) sizeof ( float ) <= sizeof (double ) <= sizeof (long double ) sizeof( int ) < = sizeof (signed int ) <= sizeof (unsigned int ) Nesneye Yonelik Programlama 2.43 Enumerated Types Bazen belli sayida deger alabilen yeni type ler olusturmak faydalidir ornek: {red, yellow, blue Bunun icin C++ da enumerated data type tanimlamak mumkundur enum color {red, yellow, blue; Default olarak 0, 1, 2,. tamsayilari birinci, ikinci, ucuncu,. elementlere map edilir color door_color = color (2); // blue Arithmetic islemlerinde enumerated type lar integer lara donusturulur (yellow + 1 == 2) nin sonucu true dur. Nesneye Yonelik Programlama 2.44