Mithat Konar (the wiki)

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~~SLIDESHOW~~

====== Programming Fundamentals ======
Mithat Konar\\ 
with material from Capron's "Essentials of Computing", 2/e

===== What is programming? =====

  * **programming**: the discipline of creating computer programs.
  * **computer program**:
    * a set of step-by-step instructions
    * that directs the computer to do the tasks you want it to do
    * and produce the results you want.
  * Programmer -> computer program -> software.

===== What programmers do =====

  * "Write programs" 
    * Prepare the instructions of a computer program.
    * Test and correct programs.
    * Document the way a program works.
    * Interact with other programmers, systems analysts, clients.

===== Programming languages =====

  * **programming language**:
     * a set of rules used to write computer programs.
     * a way of telling the computer what operations to perform.
  * Computers are //binary// machines.
    * Use only ON/OFF switches to control internal states.
    * Only understand instructions that are expressed in ON/OFF (or 1/0) terms.
  * Programming languages have been invented to make it easier for humans to write programs.

===== Levels of language =====

  * Programming languages exist on a spectrum of low to high level.
    * **low level**: close to the 1/0 language the computer directly uses.
    * **high level**: closer to natural language or mathematics.
  * Five levels:
    * machine language
    * assembly languages
    * high level languages
    * very high level languages
    * natural language programming

===== Machine language =====

<code>
10110110100100101101011101001010
10110110110101101101011011000111
</code>

  * Lowest level of language.
  * Just 1’s and 0’s.
  * Very hard not to make a mistake.
  * Each type of computer processor has its own machine language.

===== Assembly language =====

<code>
MOV AL, 1h
MOV CL, 2h
MOV DL, 3h
</code>

  * Alphanumeric abbreviations or mnemonic codes replace 1's and 0's.
    * ''ADD'' for Add, ''CMP'' for Compare, ''MOV'' for Move, etc.
  * **Assembler** program converts assembly language programs into machine language.

===== High-level languages =====
<code>
if score > 60:
    print('You passed!')
else:
    print('Try harder!')
</code>

  * Uses math-like or English-like notation systems.
  * Allows programmer to think less about language details and more about solving problems.
  * Portability

===== Very high-level languages =====

  * Try to come closer to natural language than high-level languages.

===== Natural language programming =====

  * Tries to let people program using everyday language.
	* "Show a list of names from the contact list," same as "Display the names of everyone in the contact list."

===== Kinds of translation =====

  * High-level languages need to be **translated** into machine language.
  * Three approaches:
    * **interpreted**: translate one line of the program, run it, move to the next.
    * **compiled**: translate the whole program at once. Produces a new file full of machine code.
    * **hybrid**: translate the whole program into an in-between language; execute the in-between language in an interpreter.

===== Kinds of errors =====

  * **syntax error**: you broke a language rule.
  * **semantic** or **logic error**: the program runs and doesn't complain, but it doesn't produce the desired result.
  * **runtime error**: you ask the program to do something it can't, like divide A by B when B happens to be zero.

===== Programming process =====

  - Define the problem.
  - Design a solution.
  - Code the solution.
  - Test the solution.
  - Document the solution.

===== Define the problem =====

  * Undefined problems cannot be solved.
  * May be formal or informal.
  * Sometimes simple, often not.

===== Design a solution =====

  * Design your solution before you try to build it!
  * 80/20 rule: spend 80% of your time designing, 20% writing.

===== Code the solution =====

  * Write the programming language statements and other resources you need to implement the design.

===== Test the solution =====

  * **debugging**: detecting, locating, and fixing mistakes.
  * **desk checking**: working through your code without running it to find mistakes.

===== Document the solution =====

  * **documentation**: a written detailed description of the programming cycle and specific facts about the program.
  * Most languages let you include some documentation in the program code.
  * Documentation is needed:
    * to help organize program planning
    * to help communicate with others about your program.
    * to help remind **you** what your program is doing.
  * //Very important!!!//

===== Programming tools =====

  * **code editor**: used to write the program code (i.e., **source code**).
  * **translator**: used to translate source code into a form the computer can execute.
  * **debugger**: used to interactively run a program and observe its internal state.
  * **project manager**: used to organize source code and other files associated with a program.
  * **IDE** (integrated development environment): integrates a number of these tools into one unified environment to help increase productivity.

===== Fin =====

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