Parameters provide information to a subprogram that it needs to execute successfully. In a function or procedure call, parameters are Listed after the name of the function or procedure, enclosed in parentheses.
The specification for a function or procedure defines each of the parameters it requires. The parameter names in a function or procedure declaration are referred to as formal parameters. In the following procedure syntax example, the formal parameters include window_name, width, and height:
Resize_Window (window_name, width, height);
The values of formal parameters are provided by actual parameters.
When you call the RESIZE_WINDOW procedure, you supply values for the formal parameters by referencing a specific window and specifying the desired width and height values. The values you enter in the List of parameters are actual parameters. In the following procedure call, my_window, 50, and 35 are actual parameters:
Resize_Window('my_window',50,35);
Note: To specify a single quote character as a literal character, prefix each single quote in the string with an additional single quote. For example, the actual parameter '''50'' PIXELS' is interpreted by the calling subprogram as '50' PIXELS.