College of Computer and Information Science Chapter 14 Programming and Languages

College of Computer and Information Science

Chapter 14

Programming and Languages

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Key Words & Terms• application generator: 代码生成器• assembly language: 汇编语言• beta testing: beta 测试• code: 代码• coding: 编码• compiler: 编译器• computer-aided software engineering (CASE) tools: 计算机辅助

软件工程工具• debugging: 调试 • desk checking: 桌面检测• DO UNTIL structure: 一种循环结构 DO UNTIL• DO WHILE structure: 一种循环结构 DO WHILE• documentation: 文档化• fifth-generation language (5GL): 第五代语言• formatting language: 格式化语言• fourth-generation language (4GL): 第四代语言 • generation: 代，级• higher level: 高级

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Key Words & Terms• IF-THEN-ELSE structure: 分支结构• IFPS (interactive financial planning system): 交互式财务策划系统• interpreter: 解释器• levels: 层次，级• logic error: 逻辑错• logic structure: 逻辑结构• loop structure: 循环结构• lower level: 低级• machine language: 机器语言 • maintenance programmer: 维护程序员• markup language: 标记语言• module: 模块• natural language: 自然语言• object: 对象• object code: 对象代码 • object-oriented programming (OOP): 面向对象程序设计 • object-oriented software development: 面向对象软件开发• objectives: 目标，对象

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Key Words & Terms• operators: 操作员• portable language: 可移植语言 • problem-oriented language: 面向问题语言• procedural language: 过程语言• program: 程序• program analysis: 程序分析 • program coder: 代码生成器• program definition: 程序定义 • program design: 程序设计 • program documentation: 程序文档• program flowchart: 程序流程图• program maintenance: 程序维护• program modules: 程序模块• program specification: 程序说明• programmer: 程序员 • programming: 编程，程序设计• programming language: 程序设计语言• pseudo-code: 伪码

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Key Words & Terms• query language: 查询语言 • selection structure: 选择结构 • sequence structure: 顺序结构• software development: 软件开发• software engineer: 软件工程• source code: 源代码 • structured program: 结构化程序• structured programming techniques: 结构化程序设计技术 • syntax error: 语法错• third generation language (3GL) : 第三代语言• top-down program design: 自上而下程序设计• user: 用户 • very high level language: 超高级语言 • visual programming language: 可视化程序设计语言

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Competencies (Page 1 of 2)

• Describe the six steps of programming

• Discuss design tools including top-down design, pseudocode, flowcharts, and logic structures

• Describe program testing and the tools for finding and removing errors

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Competencies (Page 2 of 2)

• Describe CASE tools and object-oriented software development

• Explain the five generations of programming languages

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Introduction

• In this chapter programming is described in two parts: (1) the steps in the programming process and (2) some of the programming languages available.

• Programming is part of Phase 4, systems development, in the systems life cycle.

• Competent end users need to understand the relationship between systems development and programming.

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Programs and Programming

• What is a Program? • A problem-solving procedure

– A list of instructions• Prewritten• Custom-written • Application software• System software

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What is Programming?

• Programming is software development• Six step procedure

– Program specification– Program design– Program code– Program test– Program documentation– Program maintenance

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Step 1: Program Specification

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• Also called programs definition or program analysis

• 5 Step Process– Program Objectives– Desired Output– Input Data– Processing Requirements– Document Program Specifications

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Program Objectives

• Objectives are the problems that you are trying to solve

• Programming requires a clear statement of the problem that you are looking to address

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Program Specification Steps Continued

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• Desired output• Input Data• Processing

Requirements• Program

Specifications Document

Example of statement of hours worked

End user’s sketch of desired output

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Step 2: Program Design

• Plan a solution• Use structured programming techniques

– Top-down program design– Pseudocode– Flowcharts– Logic structures

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Step 3: Program Code

• Writing the program or coding • The good program

– Reliable– Catch input errors – Understandable to other

programmers– Structured programs best method– Use the most appropriate

computer language

• Coding

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Coding

• Formatting or presentation language

• Programming language

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Step 4: Program Test

• Debugging– Testing – Eliminating errors

• Syntax errors• Logic errors• Testing process

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Step 5: Program Documentation

• Written descriptions and procedures about a program

• Important for people who will use the program– Users– Operators – Programmers

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Step 6: Program Maintenance

• 75% of total lifetime cost• Error-free operations • Effective program• Two categories

– Operations– Changing needs

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Case Tools

• Computer-aided software engineering (CASE)– Automate development process

• Designing• Coding• Testing activities

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Object-Oriented Software Development

• Focuses less on procedures, more on

relationship between objects

• OOP: Object-oriented programming

• Object contains both the data and the

processing operations

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Generations of Programming Languages (Page 1 of 2)

• Occurring in “generations” or “levels”– Levels-Machine languages to natural languages

• There are five generations :– Lower level closer to machine language– Higher level closer to human-like language

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• 1st -- Machine languages • 2nd -- Assembly languages• 3rd -- High level procedural languages (3GL)• 4th -- Problem-Oriented languages (4GL)• 5th -- Natural Languages & Visual

programming languages (5GL)

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Generations of Programming Languages (Page 2 of 2)

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Language Translators

• compiler

compiling linking

resource code========>.obj=======>.exe

• interpreter

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Discussion Questions (Page 1 of 2)

• Identify and discuss each of the six steps of programming.

• Describe CASE tools and OOP. How does CASE assist programmers?

• What is meant by “generation” in reference to programming languages? What is the difference between low-level and high-level languages?

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Discussion Questions (Page 2 of 2)

• What is the difference between a compiler and an interpreter?

• What are logic structures? Describe the differences between the three logic types.

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End of Chapter 14