I know how to output char
textout_ex( screen, font, "", x, y, makecol( 255, 0, 0), makecol( 0, 0, 0) );

How can I output an int?

I have looked around for documentation on it can't find anything...

Also how do I input...

You can't have looked very hard...
textprintf_ex()
It's in the manual.

Parse error. Statement too vague.

you know, input...

In my normal c++ I would normally type
cin >> example;

Where example is the value stored.

as an example...

I just tried textprintf_ex

I get
'textprintf_ex' : cannot convert parameter 7 from 'int' to 'const char *'

My mention of the manual was a hint.

Ugg took me ages to get my head around it, mental block I suppose...

int money;
textprintf_ex(screen, font, 10, 10, makecol(255, 100, 200),
1, "money: %d", money);

Input is a more complex task. I guess the best solution is to use a GUI element. If you use Allegro GUI, make a simple dialog, like:

char *my_input = "        ";
DIALOG dlg[] =
{
   /* (proc)      (x) (y) (w) (h) (fg) (bg)      (key) (flags) (d1) (d2) (dp)           (dp2) (dp3) */
   { d_edit_proc, 20, 28, 84, 16, 0,   16777215, 0,    0,      4,   0,   (void*)my_input, NULL, NULL },
   { NULL,        0,  0,  0,  0,  0,   0,        0,    0,      0,   0,   NULL,          NULL, NULL }
};

popup_dialog(dlg, -1);

After that you have your input in my_input. But RTFM, to get the size of the field correct. And to get the dialog closed properly with <enter>.

What can I use to sort of stick the GUI to the background, and when it is clicked on you can edit the field, then when I click on a button confirm it stores what is in the box.

E.g. Entering a characters name and clicking confirm.

Can you not read? It stores what's in the box automatically, seeing as dp is a pointer to 'my_input'. You use update_dialog (check the manual, don't just do do_dialog(); and expect it to work). You don't need to do anything to stick it to the screen, it does it automatically. If you need to run some code at the same time, either implement your own proc, and run it from within the dialog, or use some other code I can't quite remember, either way RTFM.

Also, see here

But it disapears... I mean, the dialog disapears, I want it to stay there till I click confirm

Did you read the Allegro GUI Clinic that I linked to? That's a great resource and also where I learnt how to use dialogs. You will need a d_screen_proc (or something like that, I don't remember the name), so that the dialog can keep control of the screen.

When people post pieces of code here, they aren't necessarily tested or complete, and you are likely to have to interpret it or add bits.

EDIT:
It's called a d_clear_proc.

EDIT2:
Or, if you want a function like Input() from Blitz Basic (I highly doubt you've heard of it, but I can't think of another example, it's similar to console input), you would just implement a loop like below, possibly in a function to make it easier to use. This code is untested, incomplete, and is pseudo-code, because I'm not in a programming mood:

while(!character == 10) { //Carriage return
  character = readkey();
  if(!character == 8 /*I _THINK_ that is backspace, check a few other keys as well. Google for an ASCII code table.*/) {
    strcat(theinput, character);
    lettercount++;
  } else {
    theinput[lettercount] = '';
    lettercount--;
  }
}

You might want to add:
A blinking cursor
Arrow Key support
Home/End Key support
Multi-Line support
Anything else I can't think of right now

Capture it as an int and use if(character>>8 == KEY_BACKSPACE)
To add the character to the string AND it with 0xFF. Example: theinput[lettercount] = character&0xff;

Or if you're using C++, just use this, which I retrieved using the "search" function:

Written by 23yrold3yrold.