{"id":153,"date":"2021-12-23T16:12:20","date_gmt":"2021-12-23T09:12:20","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=153"},"modified":"2022-05-27T10:39:37","modified_gmt":"2022-05-27T03:39:37","slug":"csharp-if-else","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-tutorial\/csharp-if-else\/","title":{"rendered":"C# if else"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn how to use the C# if else<\/code> statement to execute a block when a condition is true<\/code> and another block otherwise.<\/p>\n\n\n\n

Introduction to the C# if else statement<\/h2>\n\n\n\n

In practice, you often want to execute a block when a condition is true<\/code> and execute another block otherwise. In this case, you need to use the if else<\/code> statement.<\/p>\n\n\n\n

The following illustrates the syntax of the if else<\/code> statement:<\/p>\n\n\n

if<\/span> (condition)\n{\n    \/\/ if statements<\/span>\n}\nelse<\/span>\n{\n    \/\/ else statements<\/span>\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax, the if else<\/code> statement evaluates the condition<\/code>. If the condition<\/code> is true<\/code>, it’ll execute the if block. Otherwise, the if else<\/code> statement executes the else<\/code> block.<\/p>\n\n\n\n
The following flowchart illustrates how the if else<\/code> statement works:<\/p>\n\n\n
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\"C#<\/figure>\n<\/div>\n\n\n
C# if else statement examples<\/h2>\n\n\n\n
Let’s take some examples of using the if else<\/code> statement.<\/p>\n\n\n\n
1) Simple C# if else statement examples<\/h3>\n\n\n\n
The following example uses the if else<\/code> statement to show a message when the condition<\/code> is \"sunny\"<\/code>:<\/p>\n\n\n
string<\/span> condition = \"sunny\"<\/span>;\n\nif<\/span> (condition == \"sunny\"<\/span>)\n{\n    Console.WriteLine(\"Let's go outside.\"<\/span>);\n}\nelse<\/span>\n{\n    Console.WriteLine(\"Just stay home.\"<\/span>);\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Let's go outside.<\/span><\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the condition is \"sunny\"<\/code>. Therefore, you’ll see the message \"Let's go outside.\"<\/code> in the output.<\/p>\n\n\n\n
The following example changes the condition<\/code> to \"rainy\"<\/code>:<\/p>\n\n\n
string<\/span> condition = \"rainy\"<\/span>;\n\nif<\/span> (condition == \"sunny\"<\/span>)\n{\n    Console.WriteLine(\"Let's go outside.\"<\/span>);\n}\nelse<\/span>\n{\n    Console.WriteLine(\"Just stay home.\"<\/span>);\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Just stay home.<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Since the expression condition == \"sunny\"<\/code> is false<\/code>, the else<\/code> block executes that shows the message \"Just stay home.\"<\/code> to the output.<\/p>\n\n\n\n
2) Using if else statement with a complex condition example<\/h3>\n\n\n\n
The following example uses the if else<\/code> statement with a complex condition:<\/p>\n\n\n
string<\/span> condition = \"sunny\"<\/span>;\nbool<\/span> free = true<\/span>;\n\nif<\/span> (free & condition == \"sunny\"<\/span>)\n{\n    Console.WriteLine(\"Let's go outside.\"<\/span>);\n}\nelse<\/span>\n{\n    Console.WriteLine(\"Just stay home.\"<\/span>);\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Let's go outside.<\/span><\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the condition<\/code> is \"sunny\"<\/code> and the free<\/code> is true<\/code>. <\/p>\n\n\n\n
Because the following expression evaluates to true<\/code>:`<\/p>\n\n\n
free & condition == \"sunny\"<\/span><\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
the if<\/code> block executes to show the message \"Let's go outside.\"<\/code> to the output.<\/p>\n\n\n\n
If you change the condition<\/code> and\/or free<\/code> variables to something else that causes the expression evaluates to false<\/code>, the else<\/code> block will execute. For example:<\/p>\n\n\n
string<\/span> condition = \"sunny\"<\/span>;\nbool<\/span> free = false<\/span>;\n\nif<\/span> (free & condition == \"sunny\"<\/span>)\n{\n    Console.WriteLine(\"Let's go outside.\"<\/span>);\n}\nelse<\/span>\n{\n    Console.WriteLine(\"Just stay home.\"<\/span>);\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Just stay home.<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary<\/h2>\n\n\n\n
  • Use the C# if else<\/code> statement to execute a block when a condition is true<\/code> and another block otherwise.<\/li><\/ul>\n
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