CSCI N201

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• CSCI N201
• Programming Concepts and Database
• 4 History of Programming Languages
• Lingma Acheson
• linglu_at_iupui.edu

Department of Computer and Information Science,
IUPUI
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Progression

• Hardware
• Machine code
• Assemblers
• Compilers
• Interpreters

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Hardware encoding
Physically wiring the machine Changing the
hardware structure Programming in this way is -
Very difficult - Extremely tedious - Error
prone - Hard to fix problems
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Hardware encoding

• Change physical structure of machine
• Extremely tedious
• Very difficult
• Prone to error

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Machine Language

• Stored Language Concept
• Von Neumann
• Treat Instructions as data
• Each opcode built into ALU has a number
• Abniac
• http//wally.cs.iupui.edu/n100/update/AbApplet.ht
  ml

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Machine Language

• Abniac
• Illustrate the usage of machine languages
• All commands have a number
• Store 1
• Add 2
• Compare 3
• All cells (place holders) have a number 0 99,
  to store instructions and values
• Machine codes in second blue column
• Description in third blue column
• Output window in right most window frame

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Machine Language

• Program can be created by selecting a command,
  enter values and click on OK button
• Need to run the program after its created -
  click on Run.
• Need to tell the program where to stop running -
  click on a cell and click Halt.
• File -gt New to refresh and create a new program.

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Machine Language

• Run Abniac!
• Create your own Abniac program!

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ASCII table
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Assembler

• Mnemonics for opcodes
• E.g. use Add to mean add
• Labeled cells, e.g. cell x
• somewhat easier on programmers
• E.g. Sto 2
• Add 3
• Lod 5

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High-level Language

• Typed in near-human language
• Converted to assembler
• Much easier on programmers
• Can be assembled or compiled
• Language is still very precise, but more readable
• E.g. If (x2) then
• response.write two
• else
• response.write zero