Programming languages have evolved into different versions, I think Visual C++ allows one to build a website, but I don't think it was possible to build websites from the original C++ language.
However both C and C++ are good for building games and desktop applications since their execution speed is fast.
Java was built on top of C++, to improve upon C++ originally. I think this site details the similarities and differences between the two languages:
http://www.dickbaldwin.com/java/Java008.htm - last revised 1999.
But all programming languages have evolved now, there's .Net which includes VC++ I think. So, yeah whatever you can do with one language can also be done with another. But no two languages are exactly similar, depending on what one wants to implement on a large scale they can make a choice on which programming language to persue.
Some languages are more suitable for certain tasks than others. For example it is more straighforward to process XML files with XSLT than it is with Java, although it is possible to do it with Java.
Sometimes, when 2 languages or platforms are similar for example .Net is similar to Java, it just boils down to what platform you are more familiar with.
I learned C for 4 years in school, but when I graduated Java was being developed - but the job world didn't allow me to work on either language. I had to learn other languages like ColdFusion etc.
So pick whatever languages fascinate you and what you want to accomplish with them and learn them.
This chart lists a high level comparison between languages:
http://en.wikipedia.org/wiki/Compari...ming_languages
It is also beneficial to study the job industry and see what languages are more in demand. Some languages get discontinued or very few companies use them.