When we need to find out what is the current state of a process is (aka Running(R), Sleeping(S), Stopped(T),Zombie(Z) etc), we can use the ps command effectively.
Here is the basic setup
printf("Waiting for a console output\n");
test@shantanu>gcc simple1.c -o simple1
Waiting for a console output
........///No input is yet given
In another terminal run
test@shantanu>ps -a -o comm -o s|grep simple1
So the process is currently sleeping for my input.
All the state changes hereafter can be observed independently.