Csharp/C Sharp/Language Basics/If
Содержание
- 1 Another if else
- 2 Demonstrate a block of code
- 3 Demonstrate the if
- 4 Determine if a value is positive, negative, or zero
- 5 Determine if a value is positive or negative
- 6 If Branching
- 7 If Else
- 8 If else for int
- 9 illustrates the use of a nested if statement
- 10 Illustrates the use of an if statement that executes a block
- 11 Illustrates the use of the if statement
- 12 Logical operators with an if statement
Another if else
<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765
- /
using System;
public class NestIfValues
{
static void Main()
{
int temp = 32;
if (temp <= 32)
{
Console.WriteLine("Warning! Ice on road!");
if (temp == 32)
{
Console.WriteLine(
"Temp exactly freezing, beware of water.");
}
else
{
Console.WriteLine("Watch for black ice! Temp: {0}", temp);
}
}
}
}
</source>
Demonstrate a block of code
<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852
- /
// Demonstrate a block of code.
using System;
public class BlockDemo {
public static void Main() {
int i, j, d;
i = 5;
j = 10;
// the target of this if is a block
if(i != 0) {
Console.WriteLine("i does not equal zero");
d = j / i;
Console.WriteLine("j / i is " + d);
}
}
}
</source>
Demonstrate the if
<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852
- /
// Demonstrate the if.
using System;
public class IfDemo {
public static void Main() {
int a, b, c;
a = 2;
b = 3;
if(a < b) Console.WriteLine("a is less than b");
// this won"t display anything
if(a == b) Console.WriteLine("you won"t see this");
Console.WriteLine();
c = a - b; // c contains -1
Console.WriteLine("c contains -1");
if(c >= 0) Console.WriteLine("c is non-negative");
if(c < 0) Console.WriteLine("c is negative");
Console.WriteLine();
c = b - a; // c now contains 1
Console.WriteLine("c contains 1");
if(c >= 0) Console.WriteLine("c is non-negative");
if(c < 0) Console.WriteLine("c is negative");
}
}
</source>
Determine if a value is positive, negative, or zero
<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852
- /
// Determine if a value is positive, negative, or zero. using System;
public class PosNegZero {
public static void Main() {
int i;
for(i=-5; i <= 5; i++) {
Console.Write("Testing " + i + ": ");
if(i < 0) Console.WriteLine("negative");
else if(i == 0) Console.WriteLine("no sign");
else Console.WriteLine("positive");
}
}
}
</source>
Determine if a value is positive or negative
<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852
- /
// Determine if a value is positive or negative. using System;
public class PosNeg {
public static void Main() {
int i;
for(i=-5; i <= 5; i++) {
Console.Write("Testing " + i + ": ");
if(i < 0) Console.WriteLine("negative");
else Console.WriteLine("positive");
}
}
}
</source>
If Branching
<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765
- /
using System;
namespace Branching
{
public class TestBranching
{
static void Main()
{
int valueOne = 10;
int valueTwo = 20;
int valueThree = 30;
Console.WriteLine("Testing valueOne against valueTwo...");
if ( valueOne > valueTwo )
{
Console.WriteLine(
"ValueOne: {0} larger than ValueTwo: {1}",
valueOne, valueTwo);
}
Console.WriteLine("Testing valueThree against valueTwo...");
if ( valueThree > valueTwo )
{
Console.WriteLine(
"ValueThree: {0} larger than ValueTwo: {1}",
valueThree, valueTwo);
} // end if
} // end Main
} // end class
} // end namespace
</source>
If Else
<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765
- /
using System;
namespace Branching
{
public class TestIfElse
{
static void Main()
{
int valueOne = 10;
int valueTwo = 20;
Console.WriteLine("Testing valueOne against valueTwo...");
if ( valueOne > valueTwo )
{
Console.WriteLine(
"ValueOne: {0} larger than ValueTwo: {1}",
valueOne, valueTwo);
} // end if
else
{
Console.WriteLine(
"Nope, ValueOne: {0} is NOT larger than ValueTwo: {1}",
valueOne, valueTwo);
} // end else
} // end Main
} // end class
} // end namespace
</source>
If else for int
<source lang="csharp"> /*
* C# Programmers Pocket Consultant * Author: Gregory S. MacBeth * Email: gmacbeth@comporium.net * Create Date: June 27, 2003 * Last Modified Date: */
using System; namespace Client.Chapter_4___Program_Control {
public class ifelse
{
static void Main(string[] args)
{
int a = 5, b = 5, c = 10;
if (a == b)
Console.WriteLine(a);
if ((a > c) || (a == b))
Console.WriteLine(b);
if ((a >= c) && (b <= c))
Console.WriteLine(c);
}
}
}
</source>
illustrates the use of a nested if statement
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example4_3.cs illustrates the use of a nested if statement
- /
public class Example4_3 {
public static void Main()
{
int reactorTemp = 1500;
string emergencyValve = " ";
if (reactorTemp < 1000)
{
System.Console.WriteLine("Reactor temperature normal");
}
else
{
System.Console.WriteLine("Reactor temperature too high!");
if (emergencyValve == "closed")
{
System.Console.WriteLine("Reactor meltdown in progress!");
}
}
}
}
</source>
Illustrates the use of an if statement that executes a block
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example4_2.cs illustrates the use of an if statement that executes a block
- /
public class Example4_2 {
public static void Main()
{
int smallNumber = 5;
int bigNumber = 100;
if (bigNumber < smallNumber)
{
System.Console.Write(bigNumber);
System.Console.Write(" is less than ");
System.Console.Write(smallNumber);
}
else
{
System.Console.Write(smallNumber);
System.Console.Write(" is less than ");
System.Console.Write(bigNumber);
}
}
}
</source>
Illustrates the use of the if statement
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example4_1.cs illustrates the use of the if statement
- /
public class Example4_1 {
public static void Main()
{
int smallNumber = 5;
int bigNumber = 100;
if (bigNumber > smallNumber)
System.Console.WriteLine(bigNumber + " is greater than " +
smallNumber);
else
System.Console.WriteLine(bigNumber + " is less than " +
smallNumber);
}
}
</source>
Logical operators with an if statement
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example4_4.cs illustrates the use of logical operators with an if statement
- /
public class Example4_4 {
public static void Main()
{
int reactorTemp = 1500;
string emergencyValve = "closed";
if ((reactorTemp > 1000) && (emergencyValve == "closed"))
{
System.Console.WriteLine("Reactor meltdown in progress!");
}
}
}
</source>
