# What is exception handling?
**Exception handling** is one of the most significant parts of a good program. A decent program should be able to recognize and eliminate possible errors and exceptions. When these possible exceptions are dealt with, the developed application becomes smoother and gives the user a better experience. No one likes a program that crashes when it runs into an unexpected value.

Luckily, like some other languages, Elixir provides ways to deal with a gracefully thrown exception. One way is to use the `try/catch` method.

There are two cases that are usually handled using `try/catch`:

- `throw`
- `exit`

# **`throw`**
When writing a program, the programmer might want to stop the execution at a particular value. The program can *throw* this value whenever it is detected and then *catch* it to take necessary action. 

## Code
In this example, the programmer is running a loop through 0 to 50 and throws an exception when the remainder is equal to 4.

try do
    # For loop to generate to calculate modulo
    for x <- 0..50 do
        z = rem(x, 11)
        # Exception thrown when remainder is 4
        if x == 4, do: throw(z)
        IO.puts(x)
    end
catch
    # Exception handled accordingly
    x -> IO.puts("Caught: #{x}")
end

ElixirEnvironment

The following example shows a basic code that checks if the input string matches the pre-set string, then an exception is thrown.

try do
  IO.puts("SECURITY CLEARANCE")
  people = {"John Krasinski", "John Cena", "John Wick"}
  # Iterates over people in the tuple
  for x <- 0..3 do  
    
    name = elem(people, x)

    # If the name is John Wick, then exception is thrown
    if name == "John Wick", do: throw(name)
    IO.puts("You are clear to enter: #{name}")
  end  
catch
    # Exception handled accordingly
    name -> IO.puts("You are not clear to enter: #{name}")
end

# `exit`
In Elixir code environment, processes running inside communicate by sending signals to one another. One of these signals is the `exit` signal, which can be naturally generated when the program dies or explicitly generated by the programmer. These explicitly generated `exit` signals are handled accordingly with ``throw/catch``.

## Code
To explicitly generate an exit signal, write `exit`. Then, as soon as the exit signal is generated, instead of shutting down the program, the exception can be handled in the catch block.

try do
    exit IO.puts("exit command signaled")
catch
    _exit, _ -> IO.puts("exit caught! handle accordingly")
end

Elixir.tar.gz

What is try catch in Elixir?

Elixir uses try/catch for handling exceptions, particularly for 'throw' and 'exit' signals, ensuring smoother program execution.