The if statement in C# is used to execute a block of code if a certain condition is true. The syntax for an if statement is as follows:
1 2 3 4 5 6 | if (condition) { // Code to execute if the condition is true } |
The condition is an expression that evaluates to a boolean value (either true or false). If the condition is true, the code inside the curly braces will be executed. If the condition is false, the code will be skipped.
You can also use an else statement to specify a block of code to be executed if the condition is false. The syntax for an if…else statement is as follows:
1 2 3 4 5 6 7 8 9 10 | if (condition) { // Code to execute if the condition is true } else { // Code to execute if the condition is false } |
Here is an example of an if…else statement:
1 2 3 4 5 6 7 8 9 10 11 | int x = 10; if (x > 0) { Console.WriteLine("x is positive"); } else { Console.WriteLine("x is not positive"); } |
This code will output the following:
1 2 3 | x is positive |
You can also use an else if clause to specify additional conditions to check. The syntax for an if…else if…else statement is as follows:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | if (condition1) { // Code to execute if condition1 is true } else if (condition2) { // Code to execute if condition1 is false and condition2 is true } else { // Code to execute if both condition1 and condition2 are false } |
Examples
Here are ten examples of the if and else statements in C#:
Simple if statement:
1 2 3 4 5 6 | if (x > 0) { Console.WriteLine("x is positive"); } |
if…else statement:
1 2 3 4 5 6 7 8 9 10 | if (x > 0) { Console.WriteLine("x is positive"); } else { Console.WriteLine("x is not positive"); } |
if…else if…else statement:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | if (x > 0) { Console.WriteLine("x is positive"); } else if (x < 0) { Console.WriteLine("x is negative"); } else { Console.WriteLine("x is zero"); } |
Nested if statements:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | if (x > 0) { if (x < 10) { Console.WriteLine("x is between 0 and 10"); } else { Console.WriteLine("x is greater than 10"); } } else { Console.WriteLine("x is negative"); } |
if statement with a compound condition:
1 2 3 4 5 6 | if (x > 0 && x < 10) { Console.WriteLine("x is between 0 and 10"); } |
if statement with a bool variable:
1 2 3 4 5 6 7 | bool isPositive = x > 0; if (isPositive) { Console.WriteLine("x is positive"); } |
if statement with a nullable type:
1 2 3 4 5 6 7 8 9 10 11 | int? y = null; if (y.HasValue) { Console.WriteLine("y has a value"); } else { Console.WriteLine("y is null"); } |
if statement with an enum type:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | enum Color { Red, Green, Blue } Color c = Color.Green; if (c == Color.Green) { Console.WriteLine("c is green"); } |
if statement with a string:
1 2 3 4 5 6 7 | string s = "hello"; if (s.Length > 5) { Console.WriteLine("s has more than 5 characters"); } |
if statement with a switch statement:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | switch (x) { case 1: Console.WriteLine("x is 1"); break; case 2: Console.WriteLine("x is 2"); break; default: Console.WriteLine("x is not 1 or 2"); break; } |
