Timed Input

Is there anyone That is familiar with C++ at the moment i need help with a countdown type program I already have my code counting down but i want it to stop when the user inputs something into a variable what i have so far int seconds=5; `int user; while(seconds>0) { cout<<"\r0"<< seconds; fflush(stdout); clock_t stop = clock() + CLOCKS_PER_SEC; while(clock()<stop){} seconds--; } cout<<"\rBOOM!"; }` wanna add the user function somewhere in the loop where it stops it when a value has been passed to it