Vietnam’s president praised cooperation with Cambodia Tuesday during a private visit by King Father Norodom Sihanouk and members of the royal family, state television reported. Sihanouk arrived in Hanoi with his wife and his son, King Norodom Sihamoni, for a four-day stay. Vietnam’s President, Nguyen Minh Triet, said the visit showed relations between the two are close and important, state television said.