Invitation to Computer Science 5 th Edition Chapter 9 Introduction to High-Level Language Programming

Invitation to Computer Science 5th Edition

Chapter 9

Introduction to High-Level Language Programming

Invitation to Computer Science, 5th Edition 2

Objectives

In this chapter, you will learn about:

• The language progression

• A family of languages

• Two examples in five-part harmony

• Feature analysis

• Meeting expectations

• Software engineering

The Language Progression

• Using computers to solve problems – Often involves writing programs in a high-level

programming language


Where Do We Stand and What Do We Want?

• Disadvantages of assembly language– Programmer must “manually” manage the

movement of data items – Programmer must take a microscopic view of a task,

breaking it down into tiny subtasks at the level of what is going on in individual memory locations

– Assembly language program is machine specific– Statements are not natural-language-like


Where Do We Stand and What Do We Want? (continued)

• Expectations of a program written in a high-level language– Programmer need not manage the details of the

movement of data items within memory– The programmer can take a macroscopic view of

tasks, thinking at a higher level of problem solving



Getting Back to Binary

• Compiler– Converts high-level language instructions into

machine language instructions

• Linker– Inserts requested object code from code libraries

into the object code for the requesting program


Figure 9.1 Transitions of a High-Level Language Program


A Family of Languages

• Procedural languages– Program consists of sequences of statements that

manipulate data items– Follow directly from the Von Neumann computer

architecture– Random access memory stores and fetches values

to and from memory cells


Two Examples in Five-Part Harmony

• Favorite number– Figure 9.2 shows pseudocode algorithm – Algorithm implemented in Ada (Figure 9.3), C++

(Figure 9.4), C# (Figure 9.5), Java (Figure 9.6), and Python (Figure 9.7)


Figure 9.2 Pseudocode Algorithm for Favorite Number


Figure 9.3 Ada Program for Favorite Number


Figure 9.4 C++ Program for Favorite Number


Figure 9.5 C# Program for Favorite Number


Figure 9.6 Java Program for Favorite Number


Figure 9.6 Java Program for Favorite Number (continued)


Figure 9.7 Python Program for Favorite Number


Data Cleanup (Again)

• In this problem:– Input is a set of integer data values that may contain

0s, and 0s are considered to be invalid data– Output is to be a clean data set where the 0s have

been eliminated


Figure 9.8 The Converging-Pointers Algorithm for Data Cleanup


Figure 9.9 Ada Converging-Pointers Algorithm


Figure 9.9 Ada Converging-Pointers Algorithm (continued)


Figure 9.10 C++ Converging-Pointers Algorithm


Figure 9.10 C++ Converging-Pointers Algorithm (continued)


Figure 9.11 C# Converging-Pointers Algorithm


Figure 9.11 C# Converging-Pointers Algorithm (continued)


Feature Analysis

• If you have studied one (or more) of the online chapters for Ada, C++, C#, Java, or Python:– Compare them with the features of the other

languages by scanning Figure 9.15


Figure 9.15 Feature Analysis of Five High-Level Languages


Figure 9.15 Feature Analysis of Five High-Level Languages (continued)










Meeting Expectations

• Expectations for programs written in a high-level programming language– Programmer need not manage details of the

movement of data items within memory or pay any attention to exactly where those items are stored

– Programmer can take a macroscopic view of tasks, thinking at a higher level of problem solving


Meeting Expectations (continued)

• Expectations for programs written in a high-level programming language (continued)– Programs written in a high-level language will be

portable rather than machine specific– Programming statements in a high-level language

will be closer to natural language and will use standard mathematical notation


The Big Picture: Software Engineering

• Software development life cycle– Overall sequence of steps needed to complete a

large-scale software project

• Studies have shown that on big projects:– Initial implementation of the program may occupy

only 10–20% of the total time – 25–40% of time is spent on problem specification

and program design– 40–65% is spent on tasks that follow implementation


Figure 9.16 Steps in the Software Development Life Cycle


Scaling Up

• Figure 9.17 categorizes software products in terms of :– Size– Number of programmers needed for development– Duration of the development effort

• Software engineering – Large-scale software development


Figure 9.17 Size Categories of Software Products


The Software Development Life Cycle

• The feasibility study

• Problem specification

• Program design

• Algorithm selection or development, and analysis

• Coding


The Software Development Life Cycle (continued)

• Debugging

• Testing, verification, and benchmarking

• Documentation

• Maintenance


Modern Environments

• Integrated Development Environment– Lets programmer perform a number of tasks within

the shell of a single application program

• Rapid prototyping – Allows miscommunications between the user and

the programmer to be identified and corrected early in the development process


Summary

• In a high-level language, the programmer:– Need not manage storage – Can think about the problem at a higher level– Can use more powerful program instructions that are

more like natural language– Can write a much more portable program


Summary (continued)

• Software development life cycle– Overall sequence of steps needed to complete a

large-scale software project

Documents

Invitation to Computer Science 5 th Edition Chapter 9 Introduction to High-Level Language Programming