ctrl z linux code example

Example 1: linux how to undeo ctrl+z

ctrl +z : would suspend a command
fg + enter : bring it back

Example 2: what is the use of ctrl Z in process in linux

ctrl c is used to kill a process. It terminates your program.
ctrl z is used to pause the process. It will not terminate your program, 
it will keep your program in background.
You can restart your program from that point where you used ctrl z.