programming-for-dummies

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“Curly Bracket” Languages
True portability with Java
Although C and C++ programs are supposed to be portable — you can copy
and run them on other computers — they’re not really. Sometimes, you have
to make minor changes to get a C/C++ program to run on another computer,
but more often, you have to make major changes.
So that’s why Sun Microsystems created the Java programming language.
Like C++, Java is also based on the C language, but includes several features
to make Java programs safer than C or C++ programs. Specifically, Java isolates
the programmer from directly accessing the computer’s memory. This
reduces the power of Java somewhat, but translates into safer programs that
(hopefully) won’t crash as often as C/C++ programs do.
Perhaps the most important feature of Java is its portability. Rather than
attempt to compile a Java program into machine language for different types
of processors, Java compiles Java programs into an intermediate file format
called bytecode or pseudocode (also called p-code).
To run a Java program that’s compiled into bytecode, you need a free program,
or a Java virtual machine (VM). As long as a computer has a Java VM,
it can run a Java compiled bytecode program.
Like most promises made by computer scientists, Java programs aren’t always
portable. It’s perfectly possible to write a Java program correctly, compile it to
bytecode format, and make the program run perfectly on a specific computer
and operating system. But copy that same bytecode program to another computer,
and suddenly, the Java program doesn’t run correctly. The problem can
occur when the Java VM, on the other computer, has errors in it. So although
Java programs are more portable than C/C++ programs, they still aren’t 100
percent portable.
Besides creating full-fledged programs, like word processors or spreadsheets,
Java can also create smaller programs, or applets, which can be used
to create interactive Web pages.
So if you’re looking for a programming language that makes programming
safer and more portable, consider Java. Java programmers are in demand
almost as much as C/C++ programmers, and the similarities between Java
and C/C++ make it relatively easy to understand after you know C. (Or you
can study Java first and then study C/C++ later.)
Safer programming with C#
Microsoft took one look at C/C++ and decided they could create an improved
language, which they dubbed C# (pronounced C-sharp).