FORTRAN 90 for Scientists and Engineers

Brian H. Hahn, Brian Hahn

• Publisher: Butterworth-Heinemann
• Year: 1994
• Print ISBN: 9780340600344
• eBook ISBN: 9780080571607
• Topic: Computer Science
• Subtopic: Programming Languages
• Index: Computer Science

The introduction of the Fortran 90 standard is the first significant change in the Fortran language in over 20 years. this book is designed for anyone wanting to learn Fortran for the first time or or a programmer who needs to upgrade from Fortran 77 to Fortran 90.Employing a practical, problem-based approach this book provides a comprehensive introduction to the language. More experienced programmers will find it a useful update to the new standard and will benefit from the emphasis on science and engineering applications.

1

Getting Going

1.1 Introduction

1.2 Fortran

1.3 Running Fortran Programs

• Greetings

• AIDS cases

• Compound interest

Summary

Exercises

1.1 Introduction

In the period since I first became an undergraduate student, some 25 years ago, I have been fortunate enough to witness the remarkable revolution in computer technology which future historians will surely regard as one of the outstanding features of the twentieth century. The first computer I programmed occupied a large room. Only one person could use it at a time, by pressing an impressive array of switches, and programs had to be punched on cards. Its “fast” memory could store about 240 numbers. Its slow memory could hold a few thousand numbers, and was located on a rotating drum which you could hear ticking as it spun.

As technology advanced, and computers became more powerful, they also became much smaller. From occupying a whole room, they now only require part of a desk, a lap, or even a palm. They have banded together to form networks, and during an average working day, it is not uncommon to send electronic mail messages around the world, and to connect directly to a computer on the other side of the world.

You may not have used a computer before (except possibly to play games) but you are probably familiar with using a calculator. The simplest sort can only do arithmetic and display an answer. Smarter ones have memory locations—where intermediate results may be stored—and function keys such as sin, log, etc. The most sophisticated calculators allow you to store the sequence of operations (instructions) needed to calculate the solution of the problem. This sequence of instructions is called a program. To carry out the entire set of calculations you only need to load the program into the calculator, press the run key, supply the necessary data, and sit back while the calculator churns out the answer. A computer, whether it is a small personal one like the IBM PC, or a large impersonal mainframe, is in principle only an advanced programmable calculator, capable of storing and executing sets of instructions, called programs, in order to solve specific problems.

You may have used a computer before, but only to run software packages that have been written by someone else. Spreadsheets, databases and word processors fall into this category. If you have taken the trouble to start reading this book, you probably have an interest in science or engineering, and are curious enough about programming to want to write your own programs to solve your particular problems, instead of relying on someone else’s more general package.

1.2 Fortran

The particular set of rules for coding the instructions to a computer is called a programming language. There are many such languages, for example Fortran, BASIC, Pascal and C++. Fortran, which stands for FORmula TRANslation, was the first “high level” programming language. It made it possible to use symbolic names to represent mathematical quantities, and to write mathematical formulae in a reasonably comprehensible form, such as X = B/(2*A) The idea of Fortran was proposed in late 1953 by John Backus, in New York, and the first Fortran program was run in April 1957.

The use of Fortran spread so rapidly that it soon became necessary to standardize it, so that a program written in the standard would be guaranteed to run at any installation which claimed to support the standard. In 1966 the first ever standard for a programming language was published. This version became known as Fortran 66 (more correctly FORTRAN 66, but the practice of capitalizing acronyms is becoming unfashionable). A new standard, Fortran 77, was published in 1978. In spite of competition from newer languages such as Pascal and C, Fortran continued to flourish, so much so that the latest standard, Fortran 90, came out in August 1991. This is the version used in this book. Connoisseurs of Fortran will be interested in the history of the language sketched by Michael Metcalf and John Reid in Fortran 90 Explained, Oxford University Press (Oxford, 1990).

If you are already experienced in Fortran, you might like to consult the Preface, which indicates where the new features may be found. You will also need to know that some old features have been declared obsolescent. These (which may include some of your old favourites) have been made redundant by the new standard, and are recommended for deletion in the next stan...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Preface to Problem Solving with FORTRAN 77
• Chapter 1: Getting Going
• Chapter 2: Elementary Fortran: I
• Chapter 3: Elementary Fortran: II
• Chapter 4: Program Preparation
• Chapter 5: Decisions
• Chapter 6: Loops
• Chapter 7: Errors
• Chapter 8: Subprograms and Modules
• Chapter 9: Arrays
• Chapter 10: Advanced Input and Output
• Chapter 11: Handling Characters
• Chapter 12: Derived Types: Structures
• Chapter 13: Pointer Variables
• Chapter 14: Simulation
• Chapter 15: Matrices and Their Applications
• Chapter 16: Introduction to Numerical Methods
• Epilogue
• Appendix A: Order of Statements in a Program Unit
• Appendix B: Summary of Fortran 90 Statements
• Appendix C: Intrinsic Procedures
• Appendix D: ASCII Character Codes
• Appendix E: Solutions to Selected Exercises
• Index