A **switch statement** allows a variable to be tested against several values for equality. Each of these values is called a **case**. Once a matching case is found, its particular block of code is executed. It is an alternative to the more common *if-else* statement.

# Syntax
``` C
switch(expression)
{
   case constant_1 :
      // Code to be executed if expression == constant_1
      break;
	
   case constant_2 :
      // Code to be executed if expression == constant_2;
      break;
  
   default : // the default case is optional
      // Code to be executed if none of the cases match.
}
``` 
# Rules

There are some rules to keep in mind while writing switch statements:
- The `expression` in the switch can be a variable or an expression - but it must be an integer or a character. 
- You can have any number of cases however there should not be any duplicates. Switch statements can also be nested within each other.
- The optional `default` case is executed when none of the cases above match.
- The `break` statement is used to break the flow of control once a case block is executed. While it is optional, without it, all subsequent cases after the matching case will also get executed. Consider the code below to get a clearer idea: 

# Flow

The following diagram illustrates the flow of control in a switch:

# Examples 


Since `var = 10`, the control jumped to the `case 10` block - but without any breaks, the flow is not broken and all subsequent case statements are also printed.

Try uncommenting the `break` statements and note the output. Feel free to experiment with the value of `var` as well.

> **Note:** A `break` is not needed after the `default` case. This is because control would naturally exit the `switch` statement anyway.

int main() {
  int var = 10;
  switch (var)
    {
      case 5:
          printf("Case 1 executed.");
          // break;
      case 10:
          printf("Case 2 executed. ");
          // break;
      case 15:
          printf("Case 3 executed. ");
          // break;
      case 20:
          printf("Case 4 executed. ");
          // break;
      default:
          printf("Default case executed. ");
    }
}


You can use `char`'s for the switch expression and cases as well. In the code below, `option` matches `case 'b'`, hence its case block is executed.

int main() {

  char option = 'b';
  switch (option)
    {
      case 'a':
          printf("Case a hit.");
          break;
      case 'b':
          printf("Case b hit. ");
          break;
      case 'c':
          printf("Case c hit. ");
          break;
      default:
          printf("Default case hit.");
    }
}

How to use the switch statement in C

A switch statement tests a variable against values for equality, executing matching case blocks. Break statements prevent fall-through execution of subsequent cases.