Aren't Java and C++ similar?

[Sionofdarkness]

I've heard that Java and C++ have similarities. I always imagined them as completely different but it seems I am probably wrong. What are the similarities between them?

[WingedPanther]

To be honest, you are better off thinking of them as being completely different. They have similar syntax, and both support object-oriented programming. Beyond that, they are designed for different purposes and with very different abilities.

[Sionofdarkness]

So their syntax is similar, I always thought it was completely different. I know they have different purposes, because Java is used online and C++ isn't used for web purposes.

[WingedPanther]

That's not quite accurate, either. Java was designed to be a "compile (to byte code) once, run anywhere (in a virtual machine)" language. This makes it idea for creating applets to run in web pages, but I use a number of Java programs for stand-alone games, download utilities, etc.

On the other hand, your web browser was probably written in a combination of C and C++, which is certainly meant for "web purposes". Java was developed looking at C++ for inspiration, but C++ is a DANGEROUS language. "With great power, comes great responsibilty." Java reduced the amount of power present in the language to make it safer, particularly for applets. Java also added libraries for graphics, threading, and network communication. This makes it easier to use those facilities in Java in a predictable way. For C++ you would have to get those libraries from another source. (I'm using Boost++ and SmartWin++ at the moment).

Both Java and C++ are Turing-complete languages. Anything you can do in one can be done in the other. The difference is that Java was designed to do certain things more easily, while C++ was designed to do other things more easily. As a result, you choose the language that will suit your needs as simply and readily as possible.

I'm applying to a company that programs exclusively in Delphi. They use it because it facilitates GUI programming and database connectivity while remaining highly flexible and scalable. Their software could have been done in C++, C#, (not VB.. scalability), Java, C, Cobol, Fortran, or other languages. Delphi does the best job of meeting their needs, however, so they use that.

Each language was developed for a purpose, but most languages can accomplish the same things as any other language.

[Sionofdarkness]

Why is C++ a dangerous language? I have heard that it could crash your computer if you did something wrong, but it would have to be a really big mistake.

[WingedPanther]

I once crashed a computer on purpose using MS-BASIC. What I did was write a program that had a counter starting at 0, and started poking 0 at where the counter was. In C++, this would be like having a pointer and writing 0's to memory addresses and then moving the pointer to the next memory address. If you aren't careful, you wipe out the memory where the operating system is being stored. Windows and Linux have mechanisms to help prevent this, but you can probably see the point(er).

If my program has a pointer that can be made to point to parts of itself, and is reading input, the input could change what the program is doing and cause it to start doing very... strange... things.

[Sionofdarkness]

Why did you crash it on purpose? But that's cool, if there was a person you didn't like, or something, you could send them a program that destroys their computer. Interesting.

[WingedPanther]

I crashed it to have fun. It took longer than I expected to crash, actually.