10/9/2012. Operator is an operation performed over data at runtime. Arithmetic, Logical, Comparison, Assignment, Etc. Operators have precedence

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1 /9/22 P f Performing i Si Simple l Clcultions C l l ti with ith C#. Opertors in C# nd Opertor Precedence 2. Arithmetic Opertors 3. Logicl Opertors 4. Bitwise Opertors 5. Comprison Opertors 6. Assignment Opertors 7. Other Opertors 8. Implicit nd Explicit Type Conversions 9. Expressions 2 Opertor is n opertion performed over dt t runtime Arithmetic, Logicl, Comprison, Assignment, Etc. Opertors hve precedence Tkes one or more rguments (opernds) Produces new vlue Precedence defines which will be evluted first Expressions re sequences of opertors nd opernds tht re evluted to single vlue 4 Ctegory Opertors in C# : Unry tke one opernd Binry tke two opernds Ternry (?:) tkes three opernds Arithmetic Logicl Binry Comprison Except for the ssignment opertors, ll binry opertors re left-ssocitive The ssignment opertors nd the conditionl opertor (?:) re right-ssocitive Assignment 5 String conctention Type conversion Other Opertors * / %! ~ << >> ==!= < > <= >= = = = *= /= %= = = = <<= >>= is s typeof. [] ()?: new 6

2 /9/22 Precedence Highest Lower Opertors (postfix) new typeof (prefix) (unry)! ~ * / % << >> < > <= >= is s ==!= 8 Precedence Higher Lowest Opertors?: = *= /= %= = = <<= >>= = = = Prenthesis opertor lwys hs highest precedence Note: prefer using prentheses prentheses,, even when it seems stupid to do so 9 Arithmetic opertors,, * re the sme s in mth Division opertor / if used on integers returns integer (without rounding) or exception Division opertor / if used on rel numbers returns rell number b or Infinity fi i or NN Reminder opertor % returns the reminder from division of integers The specil ddition opertor increments vrible int squreperimeter = 7; double squreside = squreperimeter/4.; double squreare = squreside*squreside; squreside); 4.25 squreare); int = 5; int b = 4; ; b ); 9 b ); 9 b ); (b) ); b ); / 3); 3 % 3); 2 2 / 3); 4 2 2

3 /9/22 Logicl opertors tke boolen opernds nd return boolen result Opertor! turns true to flse nd flse to true Behvior of the opertors, nd ( == true, == flse) : Opertio n Opernd Opernd2 Result 5 Using the logicl opertors: bool = true; bool b = flse; b); Flse b); True b); True!b); True b true); True b true); Flse true); True true); True!); Flse (5>7) (==b)); Flse 6 3

4 /9/22 Bitwise opertor ~ turns ll to nd ll to Like! for boolen expressions but bit by bit The opertors, nd behve like, nd for boolen expressions but bit by bit The << nd >> move the bits ((left or right) g ) Behvior of the opertors, nd : Opertion Opernd ushort = 3; ushort b = 5; b); b); b); ~ b); << ); >> ); Opernd2 Result Bitwise opertors re used on integer numbers (byte, sbyte, int, uint, long, ulong) Bitwise opertors re pplied bit by bit Exmples: 9 2 Comprison opertors re used to compre vribles ==, <, >, >=, <=,!= Comprison opertors exmple: int = 5; int b = 4; Assignment opertors re used to ssign vlue to vrible, =, =, =,... Assignment opertors exmple: int x = 6; int y = 4; y *= 2); int z = y = 3; y=3 nd z=3 z); 3 x = ); x = 3); x /= 2); >= b); True!= b); True == b); Flse == ); True!= b); Flse > b); Flse

5 /9/22 Li Demo Live D String conctention opertor is used to conctente strings If the second opernd is not string, it is converted to string g utomticlly y string first = "First"; string second = "Second"; first second); FirstSecond string output = "The number is : "; int number = 5; output number); The number is : 5 Member ccess opertor. is used to ccess object members Squre brckets [] re used with rrys indexers nd ttributes Prentheses ( ) re used to override the defult opertor precedence Clss cst opertor (type) is used to cst one comptible type to nother 27 b Conditionl? x : y opertor?: hs the form Using some other opertors: int = 6; int b = 4; > b? ">b" : "b>="); >b (long) ); 6 (if b is true then the result is x else the result is y) 28 The new opertor is used to crete new objects The typeof opertor returns System.Type object (the reflection of type) The is opertor checks if n object is comptible with given type int c = b = 3; b=3; followed by c=3; c); 3 is int); True (b)/2); 4 typeof(int)); System.Int32 int d = new int(); d);

6 /9/22 Implicit Type Conversion Automtic conversion of vlue of one dt type to vlue of nother dt type Allowed when no loss of dt is possible "Lrger" types cn implicitly tke vlues of smller "types" Explicit type conversion Mnul conversion of vlue of one dt type to vlue of nother dt type Allowed only explicitly by (type) opertor Required when there is possibility of loss of dt or precision Exmple: Exmple: int i = 5; long l = i; long l = 5; int i = (int) l; Exmple of implicit nd explicit conversions: flot heightinmeters =.74f; Explicit conversion double mxheight = heightinmeters; Implicit double minheight = (double) heightinmeters; Explicit flot ctulheight = (flot) mxheight; Explicit flot mxheightflot = mxheight; Compiltion error! Note: Explicit conversion my be used even if not required by the compiler 35 6

7 /9/22 Expressions re sequences of opertors, literls nd vribles tht re evluted to some vlue Exmples: int r = (5 (5 2) / 2 5; r=7 Expression for clcultion of circle re double surfce = Mth.PI * r * r; Expression for clcultion of circle perimeter double perimeter = 2 * Mth.PI * r; 38 Expressions hs: Type (integer, rel, boolen,...) Expression of Vlue Exmples: p type int int.. Clculted C l l t d tt compile time. Expression of type int.. int Clculted t runtime. int = 2 3; = 5 int b = (3) * ( ( 4) (2* 7) / 4; b = 2 bool greter = ( > b) (( == ) (b == )); Expression of type bool.. Clculted t bool runtime. 39 We discussed the opertors in C#: Arithmetic, logicl, bitwise, comprison, ssignment nd others Opertor precedence Questions? We lerned when to use implicit nd explicit type conversions We lerned how to use expressions 4 7

8 /9/22. Write n expression tht checks if given integer is odd or even. 2. Write boolen expression tht checks for given integer if it cn be divided (without reminder) by 7 nd 5 in the sme time. 3. Write n expression tht clcultes rectngle s re by given width nd height. ht 4. Write n expression tht checks for given integer if its third digit (right-to-left) is 7. E. g. 732 true. 5. Write boolen expression for finding if the bit 3 (counting from ) of given integer is or. 6. Write n expression tht checks if given point (x, y) is within circle K(O, 5). 7. Write n expression tht checks if given positive integer number n (n ) is prime. E.g. 37 is prime. 8. Write n expression tht clcultes trpezoid's re by ygiven sides nd b nd height h. 9. Write n expression tht checks for given point (x, y) if it is within the circle K( (,), 3) nd out of the rectngle R(top=, left=, width=6, height=2).. Write boolen expression tht returns if the bit t position p (counting from ) in given integer number v hs vlue of. Exmple: v=5; p= flse Write n expression tht extrcts from given integer i the vlue of given bit number b. Exmple: i=5; b=2 vlue=. 2. We re given integer number n, vlue v (v= or ) nd position p. Write sequence of opertors tht modifies n to hold the vlue v t the position p from the binry representtion of n. Exmple: n = 5 (), p=3, v= 3 () n = 5 (), p=2, v= () 3. Write progrm tht exchnges bits 3, 4 nd 5 with bits 24,25 nd 26 of given 32-bit unsigned integer. 4. * Write progrm tht exchnges bits {p, pp,, pk-) with bits {q, q, qk-} of given 32- bit unsigned integer