SLR07 - Types of Programming Languages

Programming Paradigm

• Describes a way of doing things

• Expect languages to include facilities 

Turing complete

Languages that can solve all the problems a computer can solve

Why are different programming paradigms needed?

Some problems are better suited to being solved using a certain paradigm

Machine code

• Least abstract

• Closest to what actually happens on computer

• Programs directly to OS

• Translated into matching electrical signals

Assembly language

• Uses mnemonics, each having specific sequence 1s & 0s

• One-to-one relationship with machine code

• Translated by assembler

• Eg: LMC

High level language

• One-to-many relationship for code to machine code

• More complex

Imperative Language

• Uses sequence, selection, iteration statements that change a program’s state

• Focus on describing how a program operate

• Contains Procedural and Object Orientated Programming

Procedural programming

Program is built from one or more subroutines

Statements in procedural programming

• Sequence

• Selection

• Iteration

Object orientated programming

Focuses on a modular approach to programming

Advantages & Disadvantages of machine code & assembly language

Feature comparison of procedural & object orientated

LMC mnemonics

Opcode & Operand

• Opcode: Instruction

• Operand: Data instruction is carried out on

Immediate addressing 

• Value in address part of instruction is actually the value to be used, memory is not searched

• ADD 10 means “add 10” not add value held in memory position 10

Direct addressing

• Value in address part of instruction is a reference to the address in memory where required value is located

• ADD 10 means “find whatever is in memory location 10 and add it to accumulator”

Indirect addressing

• Value in addressing part references a memory location that contains the address in memory where required value is located

• ADD 10 = “Find memory address 10, there you will find another address, go to this address and add what is found there to accumulator”

• Useful as for larger address range as operand has only 4 bits available

Indexed addressing

• Eg. contents of an array of 100 items long has to be added together

• Need to use Index Register

• IR set to 0, so first value taken from 10 + 0

• IR incremented and same instruction = uses address 10 + 1

• This is why array needs to be stored in contiguous memory locations

• “ADD 10” = find memory address 10 plus value of IR