Why does this program print "forked!" 4 times?

Why does this program print "forked!" 4 times?

c linux unix fork systems-programming

unix

*nix select and exceptfds/errorfds semantics

c unix select systems-programming

unix

Zombie processes

c unix process posix systems-programming

unix

How to make thread in C without using POSIX library <pthread.h> [closed]

c multithreading unix systems-programming

unix

Fork implementation

c unix operating-system systems-programming

unix

Using sigaction(), c

c unix signals bitmask systems-programming

unix

Cannot step into system call source code

unix gdb systems-programming

unix

Data section in a.out

c unix operating-system systems-programming

unix

working code for Advanced Programming in the UNIX Environment 2ed preferably on Ubuntu/gcc4

linux unix operating-system systems-programming

unix

glibc documentation and endianness

linux unix endianness glibc systems-programming

unix

How to know if a process is a parent or a child

c linux unix pid systems-programming

unix

Find all files matching a given pattern AND excluding a given pattern?

bash shell unix find systems-programming

unix