IS101, Chapter 13: Programming and Languages

programming (software development)

-Actually a problem-solving procedure -List of instructions for the computer to follow to process data -Follows a six-step process know as the System Development Life Cycle

Six-Step Software Development Life Cycle

1-program specification 2-program design 3-program code 4-program test 5-program documentation 6-program test

Generation Samples

1st 111111100000001110000 2nd ADD 210(8,13), 02 B (4,7) 3rd IF(score>90) grade = 'A'; 4th SELECT client FROM daily Log WHERE service Ends >17 5th Get Patient Diagnostic from patient symptoms "sneezing", "cough", "aching"

5 generations of programming language

1st Gen: Machine languages -Data represented in 1s and 0s 2nd Gen: Assembly languages -Uses abbreviations or mnemonics that are automatically converted to the appropriate sequence of 1s and 0s 3rd Gen: High level procedural languages (3GLs) -Designed to express the logic - the procedures - that can solve general problems. Translated into machine language with a compiler or an interpreter 4th Gen: Task-oriented languages (4GLs) -Designed to solve specific problems 5th Gen: Problem and Constraint languages (5GL) -Computer languages that incorporate the concepts of artificial intelligence to allow a person to provide a system with a problem and some constraints and then request a solution

program

A list of instructions to be carried out by a computer Statements used in a programming language such as C++, Java, or Python Programs can be: -Prewritten/packaged -Custom-made

desk checking

A testing technique in which the program code is sequentially executed manually by the reviewer

syntax error

An error in a program that makes it impossible to parse — and therefore impossible to interpret.

pseudocode

An outline of the basic ideas behind how algorithms will work. -Summary of the program before it is written

Manual testing with sample data

Correct and incorrect data manually entered, results evaluated

c. Input data

Determine the source of the data

e. Documentation

Document program specifications

debugging

Finding and fixing problems in your algorithm or program.

Generations of Programming Languages

Levels or Generations -Coding from machine languages to human or natural languages There are 5 distinct generations -Lower level is closer to machine language -Higher level is closer to human-like language

2. program design

Plan a solution using structured programming techniques >techniques -Top-down design -Pseudocode -Flowcharts -Logic structures

a. Program's objectives

Requires a clear statement of the problem being addressed

d. Processing requirement

Tasks to move input to output

Testing sample data on the computer

Tests for logic errors

b. Desired output

The end-user should communicate the inputs and outputs

Program Test

The program is tested or debugged by looking for syntax and logic errors

top down program design

To identify the program's processing steps; called modules - Each module is made up of logically related program statements

Coding

Write the program -A programming language uses a collection of symbols, words, and phrases that instruct a computer to perform specific operations

Attempt at translation

Written program goes through translator program on the computer, must be syntax error-free

program language

a set of symbols and rules used to write code that can be interpreted by a computer C++ C# Java Java Script Python Swift

1. Program specification

called program definition or program analysis -Five items must be specified: a.Program's objectives b.Desired output c. Input data required d. Processing requirements e.Documentation

6. program maintenance

ensure that current programs are running error-free

logic error

program runs but does the wrong thing

beta testing

testing by a select group of potential users; users provide feedback

3. program code

writing the program is known as coding -Characteristics of a good program >Reliable >Produces the correct output >Catches common input errors >Well-documented and understandable >Structured programs - one of the best ways to code effective programs using logic structure

5. program documentation

written descriptions and procedures about a program and how to use it -Carried on throughout the programming steps Important for people who will use and/or support the program >Users need to know how to use the software >Operators need to know what to do about any error messages >Programmers may even remember all the details -Those taking over the program will need to know details