Prompt


What is a PROMPT?


A is a very helpful, special dialog. Use it to ask a question and get an answer from the user. Here is an example of a prompt:

prompt.gif

Syntax for PROMPT


PROMPT "string expression"; responseVar$

As it would look in a program:

prompt "How many would you like to purchase?";howMany

Description

The helpfile gives this description:

The PROMPT statement opens a dialog box, displays the message contained in "string expression", and waits for the user to type a response in the textbox and press the ENTER key, or press the OK or Cancel button on the dialog. The entered information is placed in responseVar$. If Cancel is pressed, then a string of zero length is returned. If responseVar$ is set to some string value before PROMPT is executed, then that value will become the "default" or suggested response that is displayed in the contained in the PROMPT dialog. This means that when the dialog is opened, the contents of responseVar$ will already be entered as a response for the user, who then has the option to either type over that 'default' response, or to press 'Return' and accept it.

Receiver Variable

If we fill the "howMany" variable before issuing a PROMPT command, the code looks like this:

    howMany=4
    prompt "How many would you like to purchase?";howMany

The prompt then looks like this, with the number 4 in the textbox. If the user presses ENTER at this point, he accepts that default answer.

prompt2.gif

Caption for the Prompt Window


If the string of text used for the prompt message has no carriage return character - chr$(13) - then the caption on the prompt dialog is blank and the string expression is the message displayed inside the dialog box. If the string expression includes a Chr$(13) then the part of the string before Chr$(13) is used as the title for the prompt dialog, and the part of the string after Chr$(13) is displayed as the message inside. Here is an example that places the word "Attention!" on the caption of the prompt.

howMany=4
prompt "Attention!" + chr$(13) + "How many?";howMany

It looks like this:
prompt2.gif

The String Expression


The string expression used in the prompt can be a literal string, a string variable, or a combination. It can consist of several strings that are added together (concatenated.) Some examples:

msg$ = "Select a " + itemType$
msg$ = name$ + color$
msg$ = "Error" + chr$(13) + "Please choose another ";name$
prompt msg$";var

Evaluating Input


When the user dismisses the PROMPT, his answer is contained in the receiver variable.

howMany=4
prompt "Attention!" + chr$(13) + "How many?";howMany
if howMany>0 then
    print "You chose to purchase ";howMany
else
    print "You cancelled the transaction."
end if

Receiver Variable Type


The examples we've used so far have a numeric receiver variable. You may use a string, too. Here's an example that uses a string receiver variable and responds to the input:

prompt "Hello!" + chr$(13) + "What is your name?";name$
if name$<>"" then
    print "It's nice to meet you, ";name$;"."
else
    print "You did not enter a name."
end if