Difference Between Function and Method (With Table)

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In the era of technology and computer, programming language plays an important role. Programming language is the way through which we can communicate with a software in a computer. Computer only understands Machine level language. The base of programming language is function and method.

Function vs Method

The main difference between function and method is that function is free of any object, whereas method itself is static or is on an object. The C language has no methods, it has only functions, whereas C++ and JAVA have no functions, they only have methods. The object-oriented word for method is, function.

A piece of code that has a name and can pass as well as optionally return data to operate on is called Function. In other words, the work of function in any programming language is to give a result in return of the data(parameters) given. A function can be used multiple times. Function can also be called upon from inside of any other function too.

While, method is known as an OOP (object-oriented programming language) because an object comprises of data and behavior and, this comprises an interface. This is how it can be determined whether an object can be utilized or not. For example – a “window” is an object which consists of methods “open” and “close” having some data and behavior.

Comparison Table Between Function and Method

Parameters of ComparisonFunctionMethod
Basis of dataOnly works with the provided data. It can access all the data linked with the class.
Data PrivacyFunction cannot operate or access private data, if any. Method can operate with the private data of the class, if any.
TypeFunctions can describe its own code. Methods are Object-oriented programming language.
Languages C language has functions and no methods. JAVA and C++ languages have methods but no function.
ClassDeclaration of class is not needed.Methods are coded inside a class.

What is Function?

Functions are a group of instructions that are bundled together to attain a specific outcome. The reusability of a particular code can be increased by a function. Any values can be passed on using variables to a function. Variables are categorised into two – arguments and parameters.

In JAVA we start the programming with a class followed by the next line stating “public static void main ()”, the ‘public’ in this denotes an access specifier and is used manage which part of the content should be accessible.

There are certain rules to be followed for defining a function in programming languages like JAVA and C++. For example, in JAVA, the rules for defining a Function are that, multiple functions having the same signature cannot be declared i.e., having the same parameters and numbers cannot be repeated. Example of a function in JAVA is given below for reference, Int findMinimum (int num1, int num2, int num3) { If (num1 > num2) return num1; { elseif (num3 > num1) return num3; else return num1; } } In C programming language, functions are of two types, predefined and user defined functions.

Functions like puts(), gets(), printf(), scanf() etc are predefined library functions. For example: – printf() function is described in <stdio.h> header file therefore, to use the printf() function, the <stdio.h> header file must be included in the program using #include <stdio.h>.

The functions that is created by the user in a program are known as user defined functions. The syntax of the user defined function is; return_type function_name (argument list) { Set of statements – Block of code } Return type can be data such as char, int, void, etc. The argument list is for comparing two return type data. The block of code is a group of C language programming statements, that will be executed whenever a call will be made to the function during the execution.

What is Method?

Methods are defined as Object-oriented programming language. Methods are also classified into three types, these are; interface method, constructor method, and implementation method.

In a programming a method is written as; String getMyName() { return “Davina Claire”; } In this above example of method, getMyName() is the method signature. { return “Davina Claire”; } is the Method Body. String is the return type and return “Davina Claire”; is the return statement.

To add methods inside a class, add the method hello() to the class; class Car { public $comp; public $color = ‘black’; public $hasSunRoof = true; public function hello() { return “beep”; } } Result: – Beep, Beep.

The full program will be; <?php // Declare the class class Car { // properties public $comp; public $color = ‘black’; public $hasSunRoof = true; // method that says hello public function hello() { return “beep”; } } // Create an instance $alto = new Car (); $swiftDzire = new Car (); // Get the values echo $alto -> color; // black echo “<br />”; echo $swiftDzire -> color; // black echo “<hr />”; // Set the values $alto -> color = ‘red’; $alto -> comp = “ALTO”; $swiftDzire -> comp = “SWIFTDZIRE”; // Get the values again echo $alto -> color; // red echo “<br />”; echo $swiftDzire -> color; // black echo “<br />”; echo $alto -> comp; // ALTO echo “<br />”; echo $swiftDzire -> comp; // SWIFTDZIRE echo “<hr />”; // Use the methods to get a beep echo $alto -> hello(); // beep echo “<br />”; echo $swiftDzire -> hello(); // beep

Main Difference Between Function and Method

  1. A function is directly called by its name, whereas a method includes a code that is called by the object’s name.
  2. A function can pass and then return the data that is operated, whereas a method operates data in a Class.
  3. A function is independent, whereas a method is a function linked with an object.
  4. Explicit data is passed on to a function, whereas a method completely passes the object on which it was called in the program.
  5. A method is Object-oriented programming while a function has standalone functionality.

Conclusion

Functions and methods are quite different and have different uses in different computer languages. A method is in itself a function in object-oriented programming language.

A function is a set of re-usable code that can be called anywhere in the program during the execution. This makes the work easier, with no need of writing the exact same code repeatedly, helping programmers writing modular codes. Both play a pivotal and essential role in the computer languages.

References

  1. https://www.sciencedirect.com/science/article/pii/S0096300309010376
  2. https://www.sciencedirect.com/science/article/pii/S0960077905004054
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