#        
## Overview

The **`case` keyword** is used in a switch statement. Each `case` expression must be unique. A `case` only takes a constant value. 

> **Note**: A `case` _cannot_ be a variable or expression.

## Syntax
```
switch(variable_expression) { 
   case constant_expr1: { 
      // statements; 
   } 
   break; 
  case constant_expr2: { 
      // statements; 
   }
   default: { 
      //statements;  
   }
   break; 
} 
```

## Example
The following code shows how to use the `case` keyword in Dart.


// dart program
void main()
{
    int num = 3;
    switch (num) {
    case 1: {
        print("Shot 1");
    } break;
    case 3: {
        print("Shot 3");
    } break;
    default: {
        print("This is default case");
    } break;
    }
}

## Explanation 

- Lines 2–16: We create the `main()` function.
 - Line 4: We declare a variable `num` of type `int` and assign a value to it.
 - Lines 5–15: We use a `switch` statement. The value of the `num` is tested against the different cases in the `switch`. If the value of `num` matches one of the cases, the corresponding code block is executed. Otherwise, the code within the default block is executed.

> **Note:** Each `case` must be unique.

What is the case keyword in Dart?

The `case` keyword in Dart, used within switch statements, requires unique, constant values and cannot involve variables or expressions.