C Programming

Implement a generic encoder$/$decoder :

$1.$ Reads the direction as a single character, $+$ means encoding $($adding key to input$),-$ means decoding $($subtracting key from input$).$

The user will be asked to provide the direction.

$2.$ Reads the user input up to the newline character.

$3.$ The key is preset.

$4.$ Supports both uppercase and lowercase letters. The letters should all be converted to lowercase before being encoded$/$decoded$.$

$5.$ As the input is read it will be encoded$/$decoded$,$ depending on the provided direction.

$->$Make sure you don$$t process the newline character!

$->$ he processed character will be printed.

Encoding$/$decoding should function as explained