It should always be enclosed between the reserved words begin and end.
Local declarations − Local declarations refer to the declarations for labels, constants, variables, functions and procedures, which are application to the body of function only.įunction Body − The function body contains a collection of statements that define what the function does. It may be standard, user-defined scalar or subrange type but it cannot be structured type. The function-type is the data type of the value the function returns. Return Type − All functions must return a value, so all functions must be assigned a type. The formal parameters list appearing in the function statement could be simple or subscripted variables, arrays or structured variables, or subprograms. These parameters may have standard data type, user-defined data type or subrange data type. Use of such formal parameters is optional. The parameter list refers to the type, order, and number of parameters of a function. This value is referred to as actual parameter or argument. When a function is invoked, you pass a value to the parameter. Here are all the parts of a function −Īrguments − The argument(s) establish the linkage between the calling program and the function identifiers and also called the formal parameters. The function header consists of the keyword function and a name given to the function. ): function_type Ī function definition in Pascal consists of a function header, local declarations and a function body. The general form of a function definition is as follows −įunction name(argument(s): type1 argument(s): type2. In Pascal, a function is defined using the function keyword. For example, function AppendStr() appends two strings, function New() dynamically allocates memory to variables and many more functions. Pascal standard library provides numerous built-in functions that your program can call. A function definition provides the actual body of the function. Every Pascal program has at least one function, which is the program itself, and all the most trivial programs can define additional functions.Ī function declaration tells the compiler about a function's name, return type, and parameters. Procedures − these subprograms do not return a value directly.Ī function is a group of statements that together perform a task. Pascal provides two kinds of subprograms −įunctions − these subprograms return a single value. This is basically called the 'Modular design.' A subprogram can be invoked by a subprogram/program, which is called the calling program. These subprograms are combined to form larger programs. A subprogram is a program unit/module that performs a particular task.
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