(i) Assembler :

An assembler is a program that converts assembly language into machine code. It takes the basic commands and operations from assembly code and converts them into binary code that can be recognized by a specific type of processor.

Assemblers are similar to compilers in that they produce executable code. However, assemblers are more simplistic since they only convert low-level code (assembly language) to machine code. Since each assembly language is designed for a specific processor, assembling a program is performed using a simple one-to-one mapping from assembly code to machine code. Compilers, on the other hand, must convert generic high-level source code into machine code for a specific processor.

(ii) Interpreter:

In computer science, an interpreter is a computer program that directly executes, i.e. performs, instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program. An interpreter generally uses one of the following strategies for program execution:

(iii)Subroutine :

A method is a subroutine defined on an object in an object oriented context.A procedure returns no values and is called in a statement, not an expression. But some languages have no statements (only expressions). The languages use some mechanism like "void context" or employ a special return value like nil or () to make functions look like procedures.A function returns a value or values and is called from within an expression.

(iv) Function

A computer has four main functions, they are Input is the data entered in to a computer from the input devices like keyboard, mouse, scanner etc. Input data can be a character, word, image etc. When you enter information (input) in to your computer a signal is send to CPU (central processing unit).

The task of performing the operations like logical and arithmetic operations is called processing. The CPU (Central Processing Unit) will perform all types of calculations based on the instructions given. It is then send to the storage unit.

• Storage
• Output
• Processing
• Input