в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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==A string can control a switch statement==

<source lang="csharp">using System;

class MainClass {
public static void Main() {
string[] strs = { "one", "two", "three", "two", "one" };

foreach(string s in strs) {
switch(s) {
case "one":
Console.Write(1);
break;
case "two":
Console.Write(2);
break;
case "three":
Console.Write(3);
break;
}
}
Console.WriteLine();

}
}</source>
<pre class=codeResult>12321</pre>

==Demonstrate the switch==

<source lang="csharp">using System;

class MainClass {
public static void Main() {
int i;

for(i=0; i<10; i++)
switch(i) {
case 0:
Console.WriteLine("i is zero");
break;
case 1:
Console.WriteLine("i is one");
break;
case 2:
Console.WriteLine("i is two");
break;
case 3:
Console.WriteLine("i is three");
break;
case 4:
Console.WriteLine("i is four");
break;
default:
Console.WriteLine("i is five or more");
break;
}
}
}</source>
<pre class=codeResult>i is zero
i is one
i is two
i is three
i is four
i is five or more
i is five or more
i is five or more
i is five or more
i is five or more</pre>

==Empty cases can fall through==

<source lang="csharp">using System;

class MainClass {
public static void Main() {
int i;

for(i=1; i < 5; i++)
switch(i) {
case 1:
case 2:
case 3: Console.WriteLine("i is 1, 2 or 3");
break;
case 4: Console.WriteLine("i is 4");
break;
}

}
}</source>
<pre class=codeResult>i is 1, 2 or 3
i is 1, 2 or 3
i is 1, 2 or 3
i is 4</pre>

==Handle two switch cases==

<source lang="csharp">using System;
class MainClass
{
public static void Main()
{
int i = 1;

switch (i)
{
case 1:
case 2:
// code here handles both 1 and 2
Console.WriteLine("Low Number");
break;

case 3:
Console.WriteLine("3");
goto case 4;

case 4:
Console.WriteLine("Middle Number");
break;

default:
Console.WriteLine("Default Number");
break;
}
}
}</source>
<pre class=codeResult>Low Number</pre>

==Put Switch statement inside a for loop==

<source lang="csharp">using System;
class MainClass
{
static void Main()
{
for (int x = 1; x < 6; x++)
{
switch (x)
{
case 2:
Console.WriteLine("x is {0} -- In Case 2", x);
break;
case 5:
Console.WriteLine("x is {0} -- In Case 5", x);
break;
default:
Console.WriteLine("x is {0} -- In Default case", x);
break;
}
}
}
}</source>
<pre class=codeResult>x is 1 -- In Default case
x is 2 -- In Case 2
x is 3 -- In Default case
x is 4 -- In Default case
x is 5 -- In Case 5</pre>

==Switch with only default==

<source lang="csharp">using System;
class MainClass
{
static void Main()
{
for (int x = 1; x < 4; x++)
{
switch (x)
{
default:
Console.WriteLine("x is {0} -- In Default case", x);
break;
}
}
}
}</source>
<pre class=codeResult>x is 1 -- In Default case
x is 2 -- In Default case
x is 3 -- In Default case</pre>

==Switch without Default==

<source lang="csharp">using System;
class MainClass
{
static void Main()
{
for (int x = 1; x < 6; x++)
{
switch (x)
{
case 5:
Console.WriteLine("x is {0} -- In Case 5", x);
break;
}
}
}
}</source>
<pre class=codeResult>x is 5 -- In Case 5</pre>

==The switch Statement==

<p>The general form of the switch statement is</p>

<source lang="csharp">switch(expression) {
case constant1:
statement sequence
break;
case constant2:
statement sequence
break;
case constant3:
statement sequence
break;
.
.
.
default:
statement sequence
break;
}</source>
<OL><LI>The switch expression must be of an integer type, such as char, byte, short, or int, or of type string .</LI><LI>The default statement sequence is executed if no case constant matches the expression.</LI><LI>The default is optional.</LI><LI>If default is not present, no action takes place if all matches fail.</LI><LI>When a match is found, the statements associated with that case are executed until the break is encountered.</LI></OL>

==The switch statement with a user input from keyboard==

<source lang="csharp">using System;

public class MainClass {
public static void Main( ) {
Console.WriteLine("Please make your selection");
Console.WriteLine("1 Hamburger");
Console.WriteLine("2 Cheese Burger");
Console.WriteLine("3 Fish");
int Selection = int.Parse( Console.ReadLine( ) );
switch( Selection ) {
case 1:
Console.WriteLine("Hamburger");
break;

case 2:
Console.WriteLine("Cheese Burger");
break;

case 3:
Console.WriteLine("Fish");
break;

default:
Console.WriteLine("Unknown choice");
break;
}
}
}</source>
<pre class=codeResult>Please make your selection
1 Hamburger
2 Cheese Burger
3 Fish
1
Hamburger</pre>

==Use a char to control the switch.==

<source lang="csharp">using System;

class MainClass {
public static void Main() {
char ch;

for(ch="A"; ch<= "E"; ch++)
switch(ch) {
case "A":
Console.WriteLine("ch is A");
break;
case "B":
Console.WriteLine("ch is B");
break;
case "C":
Console.WriteLine("ch is C");
break;
case "D":
Console.WriteLine("ch is D");
break;
case "E":
Console.WriteLine("ch is E");
break;
}
}
}</source>
<pre class=codeResult>ch is A
ch is B
ch is C
ch is D
ch is E</pre>

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в 15:31, 26 мая 2010

Admin: 1 версия