added overflow checking 	modified:   ch10/queue.h
added overflow checking
	modified:   ch10/queue.h

tushar2708/CLRS,opensourceDA/CLRS,opensourceDA/CLRS,tushar2708/CLRS,Mooophy/CLRS,tushar2708/CLRS,Mooophy/CLRS,Mooophy/CLRS,opensourceDA/CLRS,Mooophy/CLRS,tushar2708/CLRS,opensourceDA/CLRS