/*
Learning C#
by Jesse Liberty
Publisher: O'Reilly
ISBN: 0596003765
*/
using System;
namespace PassByRef
{
public class Time3
{
// private member variables
private int Year;
private int Month;
private int Date;
private int Hour;
private int Minute;
private int Second;
// Property (read only)
public int GetHour()
{
return Hour;
}
// public accessor methods
public void DisplayCurrentTime()
{
System.Console.WriteLine("{0}/{1}/{2} {3}:{4}:{5}",
Month, Date, Year, Hour, Minute, Second);
}
public void GetTime(int h, int m, int s)
{
h = Hour;
m = Minute;
s = Second;
}
// constructor
public Time3(System.DateTime dt)
{
Year = dt.Year;
Month = dt.Month;
Date = dt.Day;
Hour = dt.Hour;
Minute = dt.Minute;
Second = dt.Second;
}
}
public class PassByRefTester
{
public void Run()
{
System.DateTime currentTime = System.DateTime.Now;
Time3 t = new Time3(currentTime);
t.DisplayCurrentTime();
int theHour = 0;
int theMinute = 0;
int theSecond = 0;
t.GetTime(theHour, theMinute, theSecond);
System.Console.WriteLine("Current time: {0}:{1}:{2}",
theHour, theMinute, theSecond);
}
static void Main()
{
PassByRefTester t = new PassByRefTester();
t.Run();
}
}
}
Illustrates the use of out parameters
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example5_8.cs illustrates the use of out parameters
*/
// declare the MyMath class
class MyMath
{
// the SinAndCos() method returns the sin and cos values for
// a given angle (in radians)
public void SinAndCos(double angle, out double sin, out double cos) {
sin = System.Math.Sin(angle);
cos = System.Math.Cos(angle);
}
}
public class Example5_8
{
public static void Main()
{
// declare and set the angle in radians
double angle = System.Math.PI / 2;
// declare the variables that will be used as out paramters
double sin;
double cos;
// create a MyMath object
MyMath myMath = new MyMath();
// get the sin and cos values from the SinAndCos() method
myMath.SinAndCos(angle, out sin, out cos);
// display sin and cos
System.Console.WriteLine("sin = " + sin + ", cos = " + cos);
}
}
Passing parameters by value
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example5_6.cs illustrates passing parameters by value
*/
// declare the Swapper class
class Swapper
{
// the Swap() method swaps parameters passed by value
public void Swap(int x, int y)
{
// display the initial values
System.Console.WriteLine("In Swap(): initial x = " + x +
", y = " + y);
// swap x and y
int temp = x;
x = y;
y = temp;
// display the final values
System.Console.WriteLine("In Swap(): final x = " + x +
", y = " + y);
}
}
public class Example5_6
{
public static void Main()
{
// declare x and y (the variables whose values
// are to be swapped)
int x = 2;
int y = 5;
// display the initial values
System.Console.WriteLine("In Main(): initial x = " + x +
", y = " + y);
// create a Swapper object
Swapper mySwapper = new Swapper();
// swap the values in x and y
mySwapper.Swap(x, y);
// display the final values
System.Console.WriteLine("In Main(): final x = " + x +
", y = " + y);
}
}
Passing parameters by reference
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example5_7.cs illustrates passing parameters by reference
*/
// declare the Swapper class
class Swapper
{
// the Swap() method swaps parameters passed by reference
public void Swap(ref int x, ref int y)
{
// display the initial values
System.Console.WriteLine("In Swap(): initial x = " + x +
", y = " + y);
// swap x and y
int temp = x;
x = y;
y = temp;
// display the final values
System.Console.WriteLine("In Swap(): final x = " + x +
", y = " + y);
}
}
public class Example5_7
{
public static void Main()
{
// declare x and y (the variables whose values
// are to be swapped)
int x = 2;
int y = 5;
// display the initial values
System.Console.WriteLine("In Main(): initial x = " + x +
", y = " + y);
// create a Swapper object
Swapper mySwapper = new Swapper();
// swap the values, passing a reference to the Swap() method
mySwapper.Swap(ref x, ref y);
// display the final values
System.Console.WriteLine("In Main(): final x = " + x +
", y = " + y);
}
}
Parameter demo
/*
Learning C#
by Jesse Liberty
Publisher: O'Reilly
ISBN: 0596003765
*/
using System;
namespace ParamsDemo
{
public class TesterParamsDemo
{
public void Run()
{
int a = 5;
int b = 6;
int c = 7;
Console.WriteLine("Calling with three integers");
DisplayVals(a,b,c);
Console.WriteLine("
Calling with four integers");
DisplayVals(5,6,7,8);
Console.WriteLine("
calling with an array of four integers");
int [] explicitArray = new int[4] {5,6,7,8};
DisplayVals(explicitArray);
}
// takes a variable number of integers
public void DisplayVals(params int[] intVals)
{
foreach (int i in intVals)
{
Console.WriteLine("DisplayVals {0}",i);
}
}
[STAThread]
static void Main()
{
TesterParamsDemo t = new TesterParamsDemo();
t.Run();
}
}
}
Use regular parameter with a params parameter
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Use regular parameter with a params parameter.
using System;
class MyClass {
public void showArgs(string msg, params int[] nums) {
Console.Write(msg + ": ");
foreach(int i in nums)
Console.Write(i + " ");
Console.WriteLine();
}
}
public class ParamsDemo2 {
public static void Main() {
MyClass ob = new MyClass();
ob.showArgs("Here are some integers",
1, 2, 3, 4, 5);
ob.showArgs("Here are two more",
17, 20);
}
}
Demonstrate params
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Demonstrate params.
using System;
class Min {
public int minVal(params int[] nums) {
int m;
if(nums.Length == 0) {
Console.WriteLine(“Error: no arguments.”);
return 0;
}
m = nums[0];
for(int i=1; i < nums.Length; i++)
if(nums[i] < m) m = nums[i];
return m;
}
}
public class ParamsDemo {
public static void Main() {
Min ob = new Min();
int min;
int a = 10, b = 20;
// call with two values
min = ob.minVal(a, b);
Console.WriteLine("Minimum is " + min);
// call with 3 values
min = ob.minVal(a, b, -1);
Console.WriteLine("Minimum is " + min);
// call with 5 values
min = ob.minVal(18, 23, 3, 14, 25);
Console.WriteLine("Minimum is " + min);
// can call with an int array, too
int[] args = { 45, 67, 34, 9, 112, 8 };
min = ob.minVal(args);
Console.WriteLine("Minimum is " + min);
}
}
[/csharp]

