{"id":156,"date":"2021-12-23T22:43:59","date_gmt":"2021-12-23T15:43:59","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=156"},"modified":"2022-05-21T09:56:51","modified_gmt":"2022-05-21T02:56:51","slug":"csharp-if-else-if","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-tutorial\/csharp-if-else-if\/","title":{"rendered":"C# if else if"},"content":{"rendered":"\n

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

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

The if<\/a><\/code> statement checks one condition and executes a block if the condition is true<\/code>. <\/p>\n\n\n\n

And the if else<\/a><\/code> statement checks one condition and executes a block if the condition is true or another block otherwise. <\/p>\n\n\n\n

Both the if<\/code> and if else<\/code> statements check only one condition.<\/p>\n\n\n\n

Sometimes, you may want to check multiple conditions and execute a block if a condition is true<\/code>. To do that, you can use the if else if<\/code> statement.<\/p>\n\n\n\n

Here’s the syntax of the if else if<\/code> statement:<\/p>\n\n\n

if<\/span> (condition1)\n{\n    \/\/ block 1<\/span>\n}\nelse<\/span> if<\/span> (condition2)\n{\n    \/\/ block 2<\/span>\n}\nelse<\/span> if<\/span> (condition3)\n{\n    \/\/ block 3<\/span>\n}\nelse<\/span> \n{\n    \/\/ else block<\/span>\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax:<\/p>\n\n\n\n
  • The if else if<\/code> statement can have multiple else if<\/code> clause where each clause has a condition.<\/li>
  • The if else if<\/code> statement checks the condition1<\/code>, condition2<\/code>, … from top to bottom sequentially. If a condition is true<\/code>, the corresponding block executes. The statement will stop evaluating the remaining conditions.<\/li>
  • If no condition is true<\/code>, the block in the else<\/code> clause executes. The else<\/code> clause is optional.<\/li><\/ul>\n\n\n\n
    The following flowchart illustrates how the if else if<\/code> statement works:<\/p>\n\n\n\n
    \"C#<\/figure><\/div>\n\n\n\n
    C# if else if examples<\/h2>\n\n\n\n
    Let’s take some examples of using the if else if<\/code> statement.<\/p>\n\n\n\n
    1) Simple C# if else if statement example<\/h3>\n\n\n\n
    The following example shows how to use the if else if<\/code> statement to display the day name based on a day number entered by users:<\/p>\n\n\n
    string<\/span> dayName;\nif<\/span> (day == 1<\/span>)\n{\n    dayName = \"Sunday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 2<\/span>)\n{\n    dayName = \"Monday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 3<\/span>)\n{\n    dayName = \"Tuesday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 4<\/span>)\n{\n    dayName = \"Wednesday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 5<\/span>)\n{\n    dayName = \"Thursday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 6<\/span>)\n{\n    dayName = \"Friday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 7<\/span>)\n{\n    dayName = \"Saturday\"<\/span>;\n} \nelse<\/span>\n{\n    dayName = \"Unknown\"<\/span>;\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Output:<\/p>\n\n\n
    Monday<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
    How it works.<\/p>\n\n\n\n
    First, prompt users to input a day number between 1 and 7:<\/p>\n\n\n
    Console.WriteLine(\"Please enter a day number (1-7):\"<\/span>);\nint<\/span> day = Convert.ToInt32(Console.ReadLine());<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Second, use the if else if<\/code> statement to assign the day name to the dayName<\/code> variable based on the day number:<\/p>\n\n\n
    string<\/span> dayName;\nif<\/span> (day == 1<\/span>)\n{\n    dayName = \"Sunday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 2<\/span>)\n{\n    dayName = \"Monday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 3<\/span>)\n{\n    dayName = \"Tuesday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 4<\/span>)\n{\n    dayName = \"Wednesday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 5<\/span>)\n{\n    dayName = \"Thursday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 6<\/span>)\n{\n    dayName = \"Friday\"<\/span>;\n}\nelse<\/span> if<\/span> (day == 7<\/span>)\n{\n    dayName = \"Saturday\"<\/span>;\n} \nelse<\/span>\n{\n    dayName = \"Unknown\"<\/span>;\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Finally, output the day name to the console:<\/p>\n\n\n
    Console.WriteLine($\"It's {dayName}<\/span>.\"<\/span>);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    If you enter a day number as 5, you’ll get the following output:<\/p>\n\n\n
    Please enter a day number (1-7):\n5\nIt's Thursday.<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
    2) Using the C# if else if statement to develop a body mass index calculation program<\/h3>\n\n\n\n
    The body mass index (BMI) is a person\u2019s weight in kilograms divided by the square of height in meters. The BMI classifies a person’s weight category as underweight, healthy weight, overweight, and obesity.<\/p>\n\n\n\n
    The following program calculates the body mass index (BMI):<\/p>\n\n\n
    Console.WriteLine(\"Body Mass Index (BMI) Calculation\"<\/span>);\n\nConsole.WriteLine(\"Enter a weight (kg):\"<\/span>);\nvar<\/span> weight = Convert.ToDouble(Console.ReadLine());\n\nConsole.WriteLine(\"Enter a height (m):\"<\/span>);\nvar<\/span> height = Convert.ToDouble(Console.ReadLine());\n\n\ndouble<\/span> bmi = weight \/ (height * height);\nstring<\/span> weightStatus;\n\nif<\/span> (bmi < 18.5<\/span>)\n{\n    weightStatus = \"Underweight\"<\/span>;\n}\nelse<\/span> if<\/span> (bmi >= 18.5<\/span> && bmi <= 24.9<\/span>)\n{\n    weightStatus = \"Healthy Weight\"<\/span>;\n}\nelse<\/span> if<\/span> (bmi >= 25<\/span> && bmi <= 29.9<\/span>)\n{\n    weightStatus = \"Overweight\"<\/span>;\n}\nelse<\/span>\n{\n    weightStatus = \"Obesity\"<\/span>;\n}\n\nConsole.WriteLine($\"BMI: {bmi:0.<\/span>#}<\/span>\"<\/span>);\nConsole.WriteLine($\"Weight status:{ weightStatus}<\/span>\"<\/span>);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    How it works.<\/p>\n\n\n\n
    First, display the program heading:<\/p>\n\n\n
    Console.WriteLine(\"Body Mass Index (BMI) Calculation\"<\/span>);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Next, prompt users to enter weight in kilograms and height in meters:<\/p>\n\n\n
    Console.WriteLine(\"Enter a weight (kg):\"<\/span>);\nvar<\/span> weight = Convert.ToDouble(Console.ReadLine());\n\nConsole.WriteLine(\"Enter a height (m):\"<\/span>);\nvar<\/span> height = Convert.ToDouble(Console.ReadLine());<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Then, calculate the body mass index:<\/p>\n\n\n
    double<\/span> bmi = weight \/ (height * height);<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    After that, assign the weight status based on the BMI using the if else if<\/code> statement:<\/p>\n\n\n
    string<\/span> weightStatus;\nif<\/span> (bmi < 18.5<\/span>)\n{\n    weightStatus = \"Underweight\"<\/span>;\n}\nelse<\/span> if<\/span> (bmi <= 18.5<\/span> && bmi >= 24.9<\/span>)\n{\n    weightStatus = \"Healthy Weight\"<\/span>;\n}\nelse<\/span> if<\/span> (bmi <= 25<\/span> && bmi >= 29.9<\/span>)\n{\n    weightStatus = \"Overweight\"<\/span>;\n}\nelse<\/span>\n{\n    weightStatus = \"Obesity\"<\/span>;\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    Finally, show the BMI result:<\/p>\n\n\n
    Console.WriteLine($\"BMI: {bmi:0.<\/span>#}<\/span>\"<\/span>);\nConsole.WriteLine($\"Weight status:{ weightStatus}<\/span>\"<\/span>);<\/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 if<\/code> statement to check multiple conditions and execute a block if a condition is true.<\/li><\/ul>\n
      \n\t
      \n\t\t
      Was this tutorial helpful ?<\/div>\n\t\t
      \n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t
      \n\t\t
      \n\t\t\t
      <\/div>\n\t\t\t\n\t\t\t