C++ is a general purpose programming language invented in the early 1980s by Bjarne Stroustrup at Bell Labs. It is similar to C, invented in the early 1970s by Dennis Ritchie, but is a safer language than C and includes modern programming techniques such as object oriented programming.
You can read more about object oriented programming. In fact, C++ was originally called C with Classes and is so compatible with C that it will probably compile more than 99% of C programs without changing a line of source code.
The purpose of C++ is to precisely define a series of operations that a computer can perform to accomplish a task. Most of these operations involve manipulating numbers and text, but anything that the computer can physically do can be programmed in C++. Computers have no intelligence- they have to be told exactly what to do and this is defined by the programming language you use. Once programmed they can repeat the steps as many times as you wish at very high speed. Modern PCs are so fast they can count to a billion in a second or two.
Anybody with a Basic knowledge of computer . There is no age boundary.
Typical programming tasks include putting data into a database or pulling it out, displaying high-speed graphics in a game or video, controlling electronic devices attached to the PC or even playing music and/or sound effects. You can even write software to generate music or help you compose
Some computer languages were written for a specific purpose. Java was originally devised to control toasters, C for programming Operating Systems, Pascal to teach good programming techniques but C++ is a general purpose language and well deserves the "Swiss Pocket Knife of Languages" nickname.
There are some tasks that can be done in C++ but not very easily, for example designing GUI screens for applications. Other languages like Visual Basic, Delphi and more recently C# have GUI design elements built into them and so are better suited for this type of task. Also, some scripting languages that provide extra programmability to applications like MS Word and even Photoshop tend to be done in variants of Basic, not C++.