Displays time in proper 24 - hour format
static void displayTime ( int hh , int mm ) { if ( hh > 10 ) System . out . print ( hh + " : " ) ; else if ( hh < 10 ) System . out . print ( "0" + hh + " : " ) ; if ( mm > 10 ) System . out . println ( mm ) ; else if ( mm < 10 ) System . out . println ( "0" + mm ) ; }