hashname = Hashnew hashname[key] = value hashname[key] = value in Java

Paint Denso QR Bar Code in Java hashname = Hashnew hashname[key] = value hashname[key] = value

When defining a hash with multiple lines, use square brackets To retrieve data from a hash, identify the hash name and a key value, such as

puts hashname[ key ]

So if you wanted to retrieve data stored under the key pi , you could do the following:

hashname = Hashnew hashname[ pi ] = 314 puts hashname[ pi ]

The first line creates a hash data structure The second line stores the value 314 into the hash using the key pi The third line prints out the value identified by the pi key in the hash data structure

Ruby supports object-oriented programming To create an object, you must define a class, which specifies the properties and methods, such as

class Classname def propertyname @propertyname end def propertyname=(propertyname) @propertyname = propertyname end def methodname(parameter list) commands end end

To create an object, you must use the following syntax:

To assign a value to an object s property, you need to specify the object name and the property you want to use, such as

To tell an object to run a method, you need to specify the object name followed by the method name, such as

objectnamemethodname(parameters)

Ruby allows single inheritance, where an object can inherit from one class (in contrast to multiple inheritance, which allows an object to inherit from two or more classes) To inherit from a class, use the < symbol followed by the class name you want to inherit from, such as

class Classname def propertyname @propertyname end def propertyname=(propertyname) @propertyname = propertyname end def methodname(parameter list) commands end end class Classname2 < Classname1 # property and method definitions go here end

1: C and C++ 523 2: Java and C# 541 3: Perl and Python 559 4: Pascal and Delphi 575 5: Visual Basic and REALbasic 589

Understanding the structure of a C/C++ program Declaring variables, data types, and values Using mathematical operators Branching and looping statements Creating data structures and objects

he C language focuses on simplicity Whereas other programming languages include a large numbers of keywords, the C language consists of a much smaller number of keywords As a result, creating C compilers is relatively easy compared to creating compilers for other programming languages, which means that C compilers are easy to write for every operating system This makes it easier to transfer, or port, C programs from one computer to another Because the C language consists of relatively few keywords, it lacks features commonly found in other programming languages, such as offering a string data type To compensate for its relative sparseness of features, most C compilers include a variety of library files that contain pre-written C code that adds these useful features to the C language The main problem with C compilers is that every C compiler tends to offer different library files, so a C program designed to run on Windows may not run correctly with a different C compiler on Linux The C++ language builds on the C language by adding object-oriented features while retaining the C language s hardware access, speed, and portability Most large and complicated programs, such as operating systems, are written in C++ Because C/C++ gives complete access to all parts of the computer, a mistake in a C/C++ program can wipe out data off a hard disk or crash the entire operating system of the computer Writing C/C++ programs may be easy, but understanding and fixing C/C++ programs can be difficult Despite these problems, C/C++ is heavily used throughout the computer industry To understand programming, you must become familiar with the C/C++ programming language