# Subroutines 
Sometimes in Granite, you will need to be able to call subroutines (a kind of function) instead of jumping and be able to _return_ to where you were before. This is possible!

## New operations
* `:#`, stack push, pushes the current location to the stack, allowing a return
* `:|`, return, returns back to the previous pushed location, crashes if no location pushed

## Tutorial
Look at this program:

```
:?x
:&x,temp
:=default,temp,0
:@print
:^x
:!x
:~

:@default
:>10,x
:<print
```

This program will take a number, add 1 to it and print it out, but default to 10 if a string is passed in.

A more nicer way to do this could be with subroutines!

First, move the default label and its two operations above the prompt and define an entry label above the prompt but below the default label like this:

```
:<entry

:@default
:>10,x
:<print

:@entry
:?x
:&x,temp
:=default,temp,0
:^x
:!x
```

Now before the conditional jump to default after the type check, add a `:#` operation and replace the `:<print` operation with `:|`

The program now functions the same, but looks much more neater with subroutines!

## After example
```
:<entry

:@default
:>10,x
:|

:@entry
:?x
:&x,temp
:#
:=default,temp,0
:^x
:!x
```