Creating Subprograms and Functions in Java

Printer Quick Response Code in Java Creating Subprograms and Functions

This loop runs at least once before checking a condition If the condition is True, the loop stops The REPEAT-UNTIL loop doesn t need enclosing BEGIN-END keywords because the REPEAT and UNTIL keywords serve that function

You can create a subprogram (or a procedure) by using the PROCEDURE keyword as follows:

PROCEDURE Name (Parameter list) Const (* Constants here *) Type (* Type definitions here *) Var (* Variable declarations here *) Begin (* Commands here *); End;

Every subprogram must have a unique name, which usually describes the purpose of that subprogram (such as Calculate_Credit_Rating or DenyHealthBenefits) The parameter list declares variables to hold any data the procedure may need from another part of the program For example, a simple parameter list might look like this:

PROCEDURE Name (FirstName : string, Age : integer) Begin (* Commands here *); End;

In the preceding example, a copy of the parameter is passed to the procedure If the procedure changes the value of that data, the new value of that data appears only in the procedure and not in any other part of the program If you want a procedure to change the value of a parameter, declare that variable in the parameter list with the Var keyword, such as

PROCEDURE Name (FirstName : string, Var Age : integer); Begin (* Commands here *); End;

A function is a special version of a subprogram that always returns a single value To create a function, use the FUNCTION keyword, such as

FUNCTION FunctionName (Parameter list) : Datatype; Const (* Constants here *) Type (* Type definitions here *) Var (* Variable declarations here *) Begin (* Commands here *); FunctionName := value; End;

The two main differences between a function and a procedure are that a function needs to define the function name as a specific data type and the last line in the function must store a value into the function name

Pascal provides three data structures: Records (known as structures in C/C++) Stores multiple variables inside a single variable Arrays Stores a list of items that consist of the same data type Sets Stores an arbitrary list of items

A record is a variable that typically holds two or more variables To create a record, declare the record under the Type section and use the RECORD keyword as follows:

Type Recordname = RECORD Variables : datatype; END;

The name of a record can be any descriptive name, such as Customers or Students_1stGrade Inside a record, you must declare one or more variables like this:

Type Suckers = RECORD Name : string; Address : string; Age : integer; END;

To create an array in Pascal, you must create a variable that represents an array under the Var section of a program like this:

Var Arrayname : ARRAY [LOWERUPPER] OF datatype;

If you wanted to create an array to hold five strings, you could do this:

Var HitList : ARRAY [15] OF string;

If you don t want your array elements to be numbered from 1 to 5, you could pick any range of numbers, such as

Var HitList : ARRAY [2529] OF string;

Defining different lower and upper ranges for the size of your array gives you the flexibility of using meaningful array index numbers (such as employee IDs), but at the risk of making the actual size of the array harder to understand An array bounded by 15 easily identifies five elements in the array, but an identical array bounded by 2529 also identifies five elements in an array but it s not as obvious You can also create a dynamic array that can change in size while your program runs To create a dynamic array, define the array without specifying its size, such as

Var Arrayname : ARRAY OF datatype;