Normal completion,
Time limit exceeded,
Memory unavailable,
Bounds violation,
Protection error,
Arithmetic error,
Time overrun,
I/O failure,
Invalid instruction,
Privileged instruction,
Data misuse,
Operator or OS intervention,
Parent termination.

the most case this happened by
 1.deadlock
 2.resource is not available.
 3.CPU is not available.

one of the reasons is when process terminates is that when
it finishes executing it's final statement.

                 when parent get terminated some os not
allow the child to completes it's task so whenever the
parent get terminated it automatically make child termination