# Define M_PI 3. 14 15926535

The C++ language itself is so complicated that it is even difficult for human beings to understand its semantics. To make matters worse, due to the complexity of C++, the compilation system of C++ is very difficult to write. Even available compilers have many problems, most of which are difficult to find.

Because of its complexity, it is difficult to guarantee the correctness of complex C++ programs. Some people have also pointed out some defects, such as not supporting multithreading primitives. But so many celebrities have raised so many defects, which shows that C++ is widely used and successful.

Also known as thermonuclear reaction). Atomic bomb and man-made now