в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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==Prevent a division by zero using the ? operator==

<source lang="csharp">using System;

class Example {
public static void Main() {
int result;

for(int i = -5; i < 6; i++) {
result = i != 0 ? 100 / i : 0;
if(i != 0)
Console.WriteLine("100 / " + i + " is " + result);
}
}
}</source>
<pre class=codeResult>100 / -5 is -20
100 / -4 is -25
100 / -3 is -33
100 / -2 is -50
100 / -1 is -100
100 / 1 is 100
100 / 2 is 50
100 / 3 is 33
100 / 4 is 25
100 / 5 is 20</pre>

==Simplest Data type cast operator==

<source lang="csharp">using System;
class MyDataType
{
public static explicit operator int(MyDataType li) // Convert type
{
Console.WriteLine("explicit operator int");
return 0;
}
public static explicit operator MyDataType(int x) // Convert type
{
Console.WriteLine("public static explicit operator MyDataType");
return new MyDataType();
}
}
class MainClass
{
static void Main()
{
MyDataType d = (MyDataType)5;
int Five = (int)d;
Console.WriteLine(Five);
}
}</source>
<pre class=codeResult>public static explicit operator MyDataType
explicit operator int
0</pre>

==The ? Operator==

<OL><LI>The ? operator is often used to replace certain types of if-then-else constructions.</LI><LI>The ? is called a ternary operator because it requires three operands.</LI></OL>
<p>It takes the general form</p>

<source lang="csharp">Exp1 ? Exp2 : Exp3;</source>
<OL><LI>where Exp1 is a bool expression, and Exp2 and Exp3 are expressions.</LI><LI>The type of Exp2 and Exp3 must be the same.</LI></OL>
<p>The value of a ? expression is determined like this:</p>
<OL><LI>Exp1 is evaluated.</LI><LI>If it is true, then Exp2 is evaluated and becomes the value of the entire ? expression.</LI><LI>If Exp1 is false, then Exp3 is evaluated, and its value becomes the value of the expression.</LI></OL>

==The ternary operator==

<source lang="csharp">class MainClass
{
public static void Main()
{
int result;
result = 10 > 1 ? 20 : 10;
System.Console.WriteLine("result = " + result);
result = 10 < 1 ? 20 : 10;
System.Console.WriteLine("result = " + result);
}
}</source>
<pre class=codeResult>result = 20
result = 10</pre>

==Use ternary operator in Console.WriteLine function==

<source lang="csharp">using System;
class MainClass
{
static void Main()
{
int x = 10, y = 9;
Console.WriteLine("x is{0} greater than y",
x > y // Condition
? "" // Expression 1
: " not"); // Expression 2
y = 11;
Console.WriteLine("x is{0} greater than y",
x > y // Condition
? "" // Expression 1
: " not"); // Expression 2
}
}</source>
<pre class=codeResult>x is greater than y
x is not greater than y</pre>

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