David J. Eck - Zitate und Weisheiten

David J. Eck wurde(n) 13 mal zitiert.

When you begin a journey, it's a good idea to have a mental map of the terrain you'll be passing through.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 85-86

Different objects might respond to the same message in different ways. For example, a "print" message would produce very different results, depending on the object it is sent to. This property of objects -- that different objects can respond to the same message in different ways -- is called polymorphism.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 367-369

The OOP approach to software engineering is to start by identifying the objects involved in a problem and the messages that those objects should respond to. The program that results is a collection of objects, each with its own data and its own set of responsibilities. The objects interact by sending messages to each other.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 361-364

Java is an object-oriented programming language. What is an object? Answer: An object consists of some data together with a set of subroutines that manipulate that data. (An object is a kind of "module," or self-contained entity that communicates with the rest of the world through a well-defined interface. An object should represent some coherent concept or real-world object.)

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 21247-21250

A variable is a memory location that has been given a name so that it can easily be referred to in a program. The variable holds a value, which must be of some specified type. The value can be changed during the course of the execution of the program.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 21252-21254

Java is a "platform-independent language." What does this mean? Answer: A Java program can be compiled once into a Java Bytecode program. The compiled program can then be run on any computer that has an interpreter for the Java virtual machine. Other languages have to be re-compiled for each platform on which they are going to run. The point about Java is that it can be executed on many different types of computers without being recompiled.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 21255-21258

Programming languages differ from ordinary human languages in being completely unambiguous and very strict about what is and is not allowed in a program.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 539-540

Programming languages differ from ordinary human languages in being completely unambiguous and very strict about what is and is not allowed in a program. The rules that determine what is allowed are called the syntax of the language. Syntax rules specify the basic vocabulary of the language and how programs can be constructed using things like loops, branches, and subroutines.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 539-542

That is, the meaning of the program has to be right. The meaning of a program is referred to as its semantics. More correctly, the semantics of a programming language is the set of rules that determine the meaning of a program written in that language. A semantically correct program is one that does what you want it to.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 545-548

Using the language correctly is not the same as using it well. For example, a good program has "style." It is written in a way that will make it easy for people to read and to understand. It follows conventions that will be familiar to other programmers. And it has an overall design that will make sense to human readers. The computer is completely oblivious to such things, but to a human reader, they are paramount. These aspects of programming are sometimes referred to as pragmatics. (I will often use the more common term style.)

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 548-553

According to the syntax rules of Java, the most basic names are identifiers. Identifiers can be used to name classes, variables, and subroutines. An identifier is a sequence of one or more characters.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 632-633

Java has other types in addition to the primitive types, but all the other types represent objects rather than "primitive" data values.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 789-790

since class names and variable names are used in similar ways, it might be hard to tell which is which. Remember that all the built-in, predefined names in Java follow the rule that class names begin with an upper case letter while variable names begin with a lower case letter.

Introduction to Programming Using Java, Version 7

David J. Eck

e-Book Location: 991-993