Reference: COS240 Syllabus COS240 O-O Languages AUBG, COS dept Lecture 31 Title: C# Methods Reference: COS240 Syllabus 5/28/2018 Assoc. Prof. Stoyan Bonev

Assoc. Prof. Stoyan Bonev Lecture Contents: Structure of a C# program Accent on methods Components of a C# program Methods Types of parameters By value and by reference (out, ref) The params qualifier Named parameters Optional parameters Sample demo programs 5/28/2018 Assoc. Prof. Stoyan Bonev

Anatomy of a C# program

The Basics of a C# Program C# program: collection of classes. Classes capsulated as namespaces – named or unnamed Namespace: collection of related classes Class: collection of data items and methods Method: designed to accomplish a specific task There is a main method in every C# program. static void Main(string[] args) Main method provides the control of program flow. Java Programming: From Problem Analysis to Program Design, 4e Java Programming: From Problem Analysis to Program Design, 3e 4 4

C# Elements Figure 1-17 Relationship among C# elements C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 5 Source: Longman dictionary 1987 5

Anatomy of a Method Methods defined inside classes Group program statements Based on functionality Called one or more times All programs consist of at least one method Main( ) User-defined method C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 6 Source: Longman dictionary 1987 6

Required method /* SquareExample.cs Author: Doyle */ using System; namespace Square { public class SquareExample public static void Main( ) int aValue = 768; int result; result = aValue * aValue; Console.WriteLine(“{0} squared is {1}”, aValue, result); Console.Read( ); } Required method C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 7 Source: Longman dictionary 1987 7

Anatomy of a Method (continued) Figure 3-1 Method components C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 8 Source: Longman dictionary 1987 8

Modifiers Appear in method headings Appear in the declaration heading for classes and other class members Indicate how it can be accessed Types of modifiers Static Access C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 9 Source: Longman dictionary 1987 9

Static Modifier Indicates member belongs to the type itself rather than to a specific object of a class Main( ) must include static in heading Members of the Math class are static public static double Pow(double, double) Methods that use the static modifier are called class methods Instance methods require an object C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 10 Source: Longman dictionary 1987 10

Access Modifiers public protected internal protected internal private C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 11 Source: Longman dictionary 1987 11

Level of Accessibility C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 12 Source: Longman dictionary 1987 12

Return Type Indicates what type of value is returned when the method is completed Always listed immediately before method name void No value being returned return statement Required for all non-void methods Compatible value C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 13 Source: Longman dictionary 1987 13

Return Type (continued) public static double CalculateMilesPerGallon (int milesTraveled, double gallonsUsed) { return milesTraveled / gallonsUsed; } Compatible value (double) returned C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 14 Source: Longman dictionary 1987 14

Method Names Follow the rules for creating an identifier Examples Pascal case style Action verb or prepositional phrase Examples CalculateSalesTax( ) AssignSectionNumber( ) DisplayResults( ) InputAge( ) ConvertInputValue( ) C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 15 Source: Longman dictionary 1987 15

Parameters Supply unique data to method Appear inside parentheses Include data type and an identifier In method body, reference values using identifier name Parameter refers to items appearing in the heading Argument for items appearing in the call Formal parameters Actual arguments C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 16 Source: Longman dictionary 1987 16

Parameters (continued) public static double CalculateMilesPerGallon (int milesTraveled, double gallonsUsed) { return milesTraveled / gallonsUsed; } Call to method inside Main( ) method Console.WriteLine(“Miles per gallon = {0:N2}”, CalculateMilesPerGallon(289, 12.2)); Two formal parameters Actual arguments C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 17 Source: Longman dictionary 1987 17

Parameters (continued) Like return types, parameters are optional Keyword void not required (inside parentheses) – when there are no parameters public void DisplayMessage( ) { Console.Write(”This is “); Console.Write(”an example of a method ”); Console.WriteLine(“body. ”); return; // no value is returned } C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 18 Source: Longman dictionary 1987 18

Method Body Enclosed in curly braces Include statements ending in semicolons Declare variables Do arithmetic Call other methods Value-returning methods must include return statement C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 19 Source: Longman dictionary 1987 19

Calling Class Methods Invoke a method Call to method that returns no value [qualifier].MethodName(argumentList); Qualifier Square brackets indicate optional Class or object name Call to method does not include data type Use IntelliSense C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 20 Source: Longman dictionary 1987 20

Predefined Methods Extensive class library Console class Overloaded methods Write( ) WriteLine( ) Read( ) Not overloaded Returns an integer C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 21 Source: Longman dictionary 1987 21

Call Read( ) Methods int aNumber; Console.Write(“Enter a single character: ”); aNumber = Console.Read( ); Console.WriteLine(“The value of the character entered: ” + aNumber); Enter a single character: a The value of the character entered: 97 C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 22 Source: Longman dictionary 1987 22

Call Read( ) Methods (continued) int aNumber; Console.WriteLine(“The value of the character entered: “ + (char) Console.Read( )); Enter a single character: a The value of the character entered: a C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 23 Source: Longman dictionary 1987 23

Call ReadLine( ) Methods More versatile than the Read( ) Returns all characters up to the enter key Not overloaded Always returns a string String value must be parsed C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 24 Source: Longman dictionary 1987 24

Call Parse( ) Predefined static method All numeric types have a Parse( ) method double.Parse("string number") int.Parse("string number") char.Parse("string number") bool.Parse("string number") Expects string argument Argument must be a number – string format Returns the number (or char or bool) C# Programming: From Problem Analysis to Program Design

/* SquareInputValue.cs Author: Doyle */ using System; namespace Square { class SquareInputValue static void Main( ) string inputStringValue; double aValue, result; Console.Write("Enter a value to be squared: "); inputStringValue = Console.ReadLine( ); aValue = double.Parse(inputStringValue); result = Math.Pow(aValue, 2); Console.WriteLine("{0} squared is {1} ", aValue, result); Console.ReadKey( ); } } } // Curly braces should be lined up C# Programming: From Problem Analysis to Program Design

Call Parse( ) (continued) string sValue = " true "; Console.WriteLine (bool.Parse(sValue)); // displays True string strValue = "q"; Console.WriteLine(char.Parse(strValue)); // displays q C# Programming: From Problem Analysis to Program Design

Call Parse( ) with Incompatible Value Console.WriteLine(char.Parse(sValue)); when sValue referenced “True” Figure 3-6 System.FormatException run-time error C# Programming: From Problem Analysis to Program Design

TryParse() method The TryParse( ) method will convert a string value sent as an argument to its equivalent numeric value, but it doesn’t throw an exception when the conversion fails. Java Programming: From Problem Analysis to Program Design, 3e

TryParse( ) Method Parse( ) method and methods in Convert class convert string values sent as arguments to their equivalent numeric value If the string value being converted is invalid, program crashes as an Exception is thrown. Two ways to avoid the program crash: Could test the value prior to doing conversion with an if statement Another option is to use the TryParse( ) method C# Programming: From Problem Analysis to Program Design

TryParse( ) Method public static bool TryParse (string someStringValue, out int result) if (int.TryParse(inValue, out v1) = = false) Console.WriteLine("Did not input a valid integer - " + "0 stored in v1"); Result stored here, when conversion occurs String value returned from Console.ReadLine( ) Test…if problem, prints message, does not try to convert C# Programming: From Problem Analysis to Program Design

TryParse( ) Method Each of the built in data types have a TryParse( ) method char.TryParse( ), int.TryParse( ), decimal.TryParse( ), etc If there is a problem with the data, 0 is stored in the out argument and TryParse( ) returns false. Show LargestValue example C# Programming: From Problem Analysis to Program Design

Convert Class More than one way to convert from one base type to another System namespace — Convert class — static methods Convert.ToDouble( ) Convert.ToDecimal( ) Convert.ToInt32( ) Convert.ToBoolean( ) Convert.ToChar( ) int newValue = Convert.ToInt32(stringValue); C# Programming: From Problem Analysis to Program Design

Predefined methods C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 34

C# Programming: From Problem Analysis to Program Design 35 Source: Longman dictionary 1987 35

C# Programming: From Problem Analysis to Program Design 36 Source: Longman dictionary 1987 36

C# Programming: From Problem Analysis to Program Design 37 Source: Longman dictionary 1987 37

Math( ) Class Each call returns a value double aValue = 78.926; double result1, result2; result1 = Math.Floor(aValue); // result1 = 78 result2 = Math.Sqrt(aValue); // result2 = 8.88403061678651 Console.Write(“aValue rounded to 2 decimal places” + “ is {0}”, Math.Round(aValue, 2)); aValue rounded to 2 decimal places is 78.93 C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 38 Source: Longman dictionary 1987 38

Method Calls That Return Values In an assignment statement Line 1 int aValue = 200; Line 2 int bValue = 896; Line 3 int result; Line 4 result = Math.Max(aValue, bValue); // result = 896 Line 5 result += bValue * Line 6 Math.Max(aValue, bValue) – aValue; // result = 896 + (896 * 896 - 200) (result = 803512) Line 7 Console.WriteLine(“Largest value between {0} ” Line 8 + “and {1} is {2}”, aValue, bValue, Line 9 Math.Max(aValue, bValue)); Part of arithmetic expression Argument to another method call C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 39 Source: Longman dictionary 1987 39

Writing Your Own Class Methods [modifier(s)] returnType  MethodName ( parameterList ) {  // body of method - consisting of executable statements    } void Methods Simplest to write No return statement C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 40 Source: Longman dictionary 1987 40

Writing Your Own Class Methods – void Types A call to this method looks like: DisplayInstructions( ); public static void DisplayInstructions( ) { Console.WriteLine(“This program will determine how ” + “much carpet to purchase.”); Console.WriteLine( ); Console.WriteLine(“You will be asked to enter the ” + “ size of the room and ”); Console.WriteLine(“the price of the carpet, ” + ”in price per square yards.”); } C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 41 Source: Longman dictionary 1987 41

Writing Your Own Class Methods – void Types (continued) public static void DisplayResults(double squareYards, double pricePerSquareYard) { Console.Write(“Total Square Yards needed: ”); Console.WriteLine(“{0:N2}”, squareYards); Console.Write(“Total Cost at {0:C} “, pricePerSquareYard); Console.WriteLine(“ per Square Yard: {0:C}”, (squareYards * pricePerSquareYard)); } static method called from within the class where it resides To invoke method – DisplayResults(16.5, 18.95); C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 42 Source: Longman dictionary 1987 42

Value-Returning Method Has a return type other than void Must have a return statement Compatible value Zero, one, or more data items may be passed as arguments Calls can be placed: In assignment statements In output statements In arithmetic expressions Or anywhere a value can be used C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 43 Source: Longman dictionary 1987 43

Value-Returning Method (continued) public static double GetLength( ) { string inputValue; int feet, inches; Console.Write(“Enter the Length in feet: ”); inputValue = Console.ReadLine( ); feet = int.Parse(inputValue); Console.Write(“Enter the Length in inches: “); inches = int.Parse(inputValue); return (feet + (double) inches / 12); } Return type→ double double returned C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 44 Source: Longman dictionary 1987 44

Types of Parameters C# offers both Call by value parameters (default type) Call by reference parameters C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 45 Source: Longman dictionary 1987 45

Assoc. Prof. Stoyan Bonev Variables can hold either value types or reference types Value type where a variable X contains a value type, it directly contains an entity with some value. No other variable Y can directly contain the object contained by X (although Y might contain an entity with the same value). Reference type where a variable X contains a reference type, what it directly contains is something that refers to an object. Another variable Y can contain a reference to the same object referred to by X. Reference types actually hold the value of a memory address occupied by the object they reference. 5/28/2018 Assoc. Prof. Stoyan Bonev 46

Assoc. Prof. Stoyan Bonev 5/28/2018 Assoc. Prof. Stoyan Bonev 47

Types of Parameters Call by value Other types of parameters Copy of the original value is made Other types of parameters ref out params ref and out cause a method to refer to the same variable that was passed into the method. Useful when there is need to return more than one value C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 48 Source: Longman dictionary 1987 48

Types of Parameters When you use ref/out, call by reference is assumed. You must include ref/out both in the call (actual argument) and in the method heading (formal parameter). They must match. The ref keyword cannot be used unless the original argument is initialized before it is sent to the method. This restriction does not exist for out. C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 49 Source: Longman dictionary 1987 49

Types of Parameters Demo program Methods1.cs C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 50 Source: Longman dictionary 1987 50

Types of Parameters Demo program parameters.cs C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 51 Source: Longman dictionary 1987 51

Types of Parameters (continued) Figure 3-9 Call by reference versus value C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 52 Source: Longman dictionary 1987 52

Types of Parameters Call by value Other types of parameters Copy of the original value is made Other types of parameters ref out params ref and out cause a method to refer to the same variable that was passed into the method C# Programming: From Problem Analysis to Program Design

Upon return from TestDefault Parameters Example // Code pulled from Parameters.cs solutions int testValue = 1; TestDefault(testValue); Console.WriteLine("Upon return from TestDefault " + "Value: {0}", testValue); Console.WriteLine( ); public static void TestDefault(int aValue) { aValue = 111; Console.WriteLine("In TestDefault - Value: {0}", aValue); } Upon return from TestDefault Value: 1 C# Programming: From Problem Analysis to Program Design

Parameters Example (continued) // Code pulled from Parameters.cs solutions int testValue = 1; TestRef(ref testValue); Console.WriteLine("Upon return from TestRef " + "Value: {0}", testValue); Console.WriteLine( ); public static void TestRef (ref int aValue) { aValue = 333; Console.WriteLine("In TestRef - Value: {0}", aValue); } Upon return from TestRef Value: 333 C# Programming: From Problem Analysis to Program Design

Parameters Example (continued) // Code pulled from Parameters.cs solutions int testValue2; TestOut(out testValue2); Console.WriteLine("Upon return from TestOut " + "Value: {0}", testValue2); Console.WriteLine( ); public static void TestOut (out int aValue) { aValue = 222; Console.WriteLine("In TestOut - Value: {0}", aValue); } Upon return from TestOut Value: 222 C# Programming: From Problem Analysis to Program Design

Parameters.cs Figure 3-8 Output from ParameterClass example C# Programming: From Problem Analysis to Program Design

Types of Parameters (continued) Figure 3-9 Call by reference versus value C# Programming: From Problem Analysis to Program Design

Testing Parameters App Comment/uncomment sections while testing Figure 3-10 Visual Studio comment out icon C# Programming: From Problem Analysis to Program Design

Demo Programs and Exercises Java Programming: From Problem Analysis to Program Design, 3e

Demo Programs and Exercises Write a method with two integer parameters and no return value which swaps/exchanges/ the values of its parameters. Test the method with value parameters Test the method with ref parameters Test the method with out parameters Java Programming: From Problem Analysis to Program Design, 3e

Demo Programs // PP parameter passing mechanisms - swap by value public static void swapByVal(int pa, int pb) { int temp; temp = pa; pa = pb; pb = temp; } //=================================== // Test PP parameter passing mechanisms by value int a, b; a = 20; b = 50; Console.WriteLine("Before swapByVal a={0}, b={1}", a, b); swapByVal(a, b); Console.WriteLine(" After swapByVal a={0}, b={1}", a, b); Java Programming: From Problem Analysis to Program Design, 3e

Demo Programs // PP parameter passing mechanisms - swap by ref public static void swapByRef1(ref int pa, ref int pb) { int temp; temp = pa; pa = pb; pb = temp; } //============================================ // Test PP parameter passing mechanisms by ref int a, b; a = 70; b = 90; Console.WriteLine("Before swapByRef1 a={0}, b={1}", a, b); swapByRef1(ref a, ref b); Console.WriteLine(" After swapByRef1 a={0}, b={1}", a, b); Java Programming: From Problem Analysis to Program Design, 3e

Demo Programs // PP parameter passing mechanisms - swap by out public static void swapByRef2(out int pa, out int pb) { pa = 230; pb = 250; } //================================ // Test PP parameter passing mechanisms by out int c, d; // both vars not initialized Console.WriteLine("Before swapByRef2 c={0}, d={1}", c, d); swapByRef2(out c, out d); Console.WriteLine(" After swapByRef2 c={0}, d={1}", c, d); Java Programming: From Problem Analysis to Program Design, 3e

Params Parameter Keyword params used Appears in formal parameter list (heading to the method) Must be last parameter listed in the method heading Indicates number of arguments to the method that may vary C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 65 Source: Longman dictionary 1987 65

Params Parameters When a method uses the params modifier, the parameter is considered a parameter array. It is used to indicate that the number of arguments to the method may vary. The params argument appears in method heading only. It is prefix of a formal parameter – array identifier and must be the last parameter listed. That formal parameter cannot be defined as ref or as out parameter. Demo program VaryingArguments.cs C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 66

Types of Parameters Demo program VaryingArguments.cs C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 67 Source: Longman dictionary 1987 67

Params Parameters using System; namespace VaryingArguments { class VaryingArguments public static void Main() DisplayItems(1, 2, 3, 5); int[] anArray = new int[5] {100, 200, 300, 400, 500}; DisplayItems(anArray); DisplayItems(1500, anArray[1] * anArray [2]); } public static void DisplayItems(params int[] item) for ( int i = 0 ; i < item.Length ; i++ ) { Console.Write(item[i] + "\t"); } Console.WriteLine(); } // end of class } // end of namespace C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 68

Params Parameters Demo program VaryingArguments.cs A method may be called with a single value. Another call to the same method may send 4, or 10, or 100 values, or an array of values A variable number of arguments are accepted when params argument is included. Makes method very flexible. C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 69

Evolution of the routine concept applied to C# methods Demo Programs Evolution of the routine concept applied to C# methods

Method Evolution Overloaded methods Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution public static void displaystr() { for(int i=1; i<=1; i++) { Console.WriteLine("Bulgaria"); } Console.WriteLine("\n"); } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution public static void displaystr(int pn) { for(int i=1; i<=pn; i++) { Console.WriteLine("Bulgaria"); } Console.WriteLine("\n"); } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution public static void displaystr(String ps) { for(int i=1; i<=1; i++) { Console.WriteLine(ps); } Console.WriteLine("\n"); } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution public static void displaystr(String ps, int pn) { for(int i=1; i<=pn; i++) { Console.WriteLine(ps); } Console.WriteLine("\n"); } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution public static void displaystr() { for(int i=1; i<=1; i++) { Console.WriteLine("Bulgaria"); } } //======================================================== public static void displaystr(String ps) for(int i=1; i<=1; i++) { Console.WriteLine(ps); } public static void displaystr(int pn) for(int i=1; i<=pn; i++) { Console.WriteLine("Bulgaria"); } public static void displaystr(String ps, int pn) for(int i=1; i<=pn; i++) { Console.WriteLine(ps); } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution Overloaded methods // Test PP overloaded methods displaystr(); displaystr("Germany"); displaystr(2); displaystr("United Kingdom", 4); Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution Default arguments methods Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution Default arguments methods // // PP default arguments methods public static double aveVal(int pa=10, int pb=20, int pc=30, int pd=40) { return ( pa + pb + pc + pd ) / 4.0; } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution Default arguments methods // // Test PP default arguments functions Console.WriteLine("\n {0}", aveVal()); Console.WriteLine("\n {0}", aveVal(100)); Console.WriteLine("\n {0}", aveVal(100, 200)); Console.WriteLine("\n {0}", aveVal(100, 200, 300)); Console.WriteLine("\n {0}", aveVal(100, 200, 300, 400)); Java Programming: From Problem Analysis to Program Design, 3e

Optional Parameters May assign default values to parameters When you assign a default value to a parameter, it then becomes an optional parameter public static void DoSomething(string name, int age = 21, bool currentStudent = true, string major = "CS") Can now call DoSomething( ) and send in arguments for the default value or the default values will be assigned to the parameters C# Programming: From Problem Analysis to Program Design

Method Evolution Named parameters Java Programming: From Problem Analysis to Program Design, 3e

Named Parameters Named arguments free you from the need to remember or to look up the order of parameters for the method call DoSomething (name: “Robert Wiser", age: 20); DoSomething (name: "Paul Nelson", major: “IS"); DoSomething (name: “Fred Terrell", age: 25, major: “BUS"); C# Programming: From Problem Analysis to Program Design

Method Evolution An artefact with C# methods Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution An artefact with C# methods Given a method int add(int pa, int pb) { return pa + pb; } Java Programming: From Problem Analysis to Program Design, 3e

Method Evolution An artefact with C# methods Are the call statements valid? int a = 20, b = 50; int x = add(5, 6); int y = add(a, b);; Int z = add(a + 5 * 6, b – 7 * 8); Int t = add(a = 5 * 6, b = 7 * 8); Java Programming: From Problem Analysis to Program Design, 3e

Practical session Expand the program Methods1.cs adding more methods that reside in the same class with method Main(): Iterative GCD – gcdi() Iterative/Recursive factorial – facti(), factr() Iterative/Recursive Fibonacci – fiboi(), fibor() Iterative/Recursive Sum(1..n) – sumi(), sumr() Iterative/Recursive Power operator simulator – powi(), powr() C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 87

Practical session Expand the program Parameters.cs adding more methods that reside in the same class with method Main(): Method void swap(int pa, int pb) that exchanges the values of its parameters/arguments Test the swap method with: Input parameters by value Output ref parameters Output out parameters C# Programming: From Problem Analysis to Program Design C# Programming: From Problem Analysis to Program Design 88

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