Title: Flag of the Soviet Union
Content:  square. ; 4) The distance of the vertical axis of the star, hammer and sickle from the hoist is 1⁄3 of the flag's height. The distance from the upper side of the flag to the center of the star is 1⁄8 of the flag's height. The flag of the Soviet Union consisted of a plain red flag with a gold hammer crossed with a gold sickle placed beneath a gold-bordered red star. This symbol is in the upper left canton of the red flag. The colour red honours the red flag of the Paris Commune of 1871 and the red star and hammer and sickle are 
Title: Red star
Content:  Some red stars adopted in emblems and flags have a significance that does not originally relate to socialism. Among these, the most well-known include the current state flag of California (echoing the Californian red star flag of 1836) and the flag of New Zealand (designed in 1869, officially adopted in 1902). The flag of the District of Columbia (designed in 1921, adopted in 1938) recalls George Washington's coat of arms. DC comics' Wonder Woman also wears a 5 point red star headband with gold or yellow background.
Title: Flag of the United States
Content:  The flag of the United States of America, often referred to as the American flag or the U.S. flag, is the national flag of the United States. It consists of thirteen equal horizontal stripes of red (top and bottom) alternating with white, with a blue rectangle in the canton (referred to specifically as the "union") bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows, where rows of six stars (top and bottom) alternate with rows of five stars. The 50 stars on the flag represent the 50 states of the United States of America, and the 13 stripes represent the thirteen British colonies that declared independence from the Kingdom of Great Britain, and became the first states in the U.S. Nicknames for the flag include the Stars and Stripes, Old Glory, and the Star-Spangled Banner.
Title: Flag of the President of the United States
Content:  gold and silver fringed border. The dimensions of the flag were 8 x, and the dimensions of the color were 4 x. The flag was scarlet, with a large blue star in the middle outlined in white which contained the Great Seal. There were four white stars, one in each corner, and scattered between the angles of the large central star were 45 small white stars, representing the 45 states. This flag was placed in the cabinet room in the White House during the war, and was first shown in public during peace jubilee celebrations in Chicago and Philadelphia in October, 1898. In 1908, following the admission of Oklahoma as a state, a 46th star was added at the bottom. One of these flags was given to Theodore Roosevelt as a gift, and one hangs today in Roosevelt's home at Sagamore Hill.
Title: Flag of China
Content:  The flag of China, officially the National Flag of the People's Republic of China, also known as the Five-star Red Flag, is a Chinese red field with five golden stars charged at the canton. The design features one large star, with four smaller stars in an arc set off towards the fly. It has been the national flag of China since the foundation of the People's Republic of China on 1 October 1949. The red represents the Chinese Communist Revolution and the five stars and their relationships to each other represent the unity of the Chinese people under the leadership of the Chinese Communist Party (CCP). The flag was first hoisted by the People's Liberation Army (PLA) on a pole overlooking Beijing's Tiananmen Square on 1 October 1949, at a ceremony proclaiming the establishment of the People's Republic of China.
Title: Red star
Content:  By March 2010, the Russian government readopted the Soviet red star (but now with a blue outline reflecting the three colors – white, blue and red – of the Russian flag) as a military insignia. The Russian Air Force used this star as a roundel up to 2013, when Russia re-instated the Soviet-era red star. the Armed Forces of Belarus still use the old Soviet red star. The coat of arms of Armed Forces of the Republic of Kazakhstan includes a modified version of the Soviet red star.
Title: Flag of the United States
Content: Star Spangled Banner Flag (1814) – Flag that flew over Fort McHenry during a British bombardment in the War of 1812. This flag is depicted by Francis Scott Key in the song "Star-Spangled Banner" which would later become the national anthem of the United States.                                                                                                                                 Details :                                                                                                                                                                                                                                                                           30 x 34 ft. (Currently)                                                                                                                                                                                                                                                      15 horizontal stripes alternating red and white stripes 14 stars (one missing)                                                                                                                                                                                                                                                          Stars arranged in a staggered 3-3-3-3-3 pattern 
Title: Hero of the Russian Federation
Content:  The insignia of the title of "Hero of the Russian Federation" is also called the "Gold Star" medal (медаль "Золотая Звезда"), its design is similar to the Soviet variant. The "Gold Star" medal is a gold five-pointed star with smooth 15mm dihedral rays on the obverse. The otherwise plain reverse bears the prominent relief inscription in 2mm high letters "HERO OF RUSSIA" ("ГЕРОЙ РОССИИ") at its centre, in the upper portion, the award serial number in 1mm high numbers. The insignia is secured to a standard Russian square mount by a ring through the suspension loop. The mount is covered by a silk moiré tricolour ribbon of white, blue, and red. The insignia of Hero of the Russian Federation is worn on the left side of the chest above all other medals and decorations. It is always worn in full size; there is no ribbon bar or rosette that can be worn in lieu of the medal. When worn together with Soviet-era hero titles (Hero of the Soviet Union, Hero of Socialist Labour), the Russian title has precedence.
Title: Service flag
Content:  States. When displayed with the national flag, the latter should take the place of honor. If the flags displayed differ in size, the national flag should be larger. Blue and gold are the only colors specified for use, but silver stars are increasingly in use to represent those discharged from service because of wounds or being invalided home. The Silver Star Families of America is an organization attempting to encourage the U.S. Congress to make the Silver Star Service Banner official for those wounded or injured in a war zone. Forty-nine states, Guam, Saipan, the U.S. Virgin Islands, the Chickasaw Nation and over 2,700 cities and counties have issued proclamations in support of the Silver Star Banner and of Silver Star Service Banner Day on May 1 
Title: Order of the Red Star
Content:  The Order of the Red Star is a red enamelled 47mm to 50mm wide (depending on the variant) silver five pointed star. In the center of the obverse, an oxydised silver shield bearing the image of an erect soldier wearing an overcoat and carrying a rifle, along the shield's entire circumference, a narrow band bearing the Communist motto in relief, "Workers of the world, unite!" («Пролетарии всех стран, соединяйтесь!»), the band below the soldier bore the relief inscription "USSR" («СССР»). Below the shield, the hammer and sickle also of oxydised silver. The otherwise plain reverse bore the maker's mark and the award serial number. The Order was attached to clothing by a threaded stud and screw attachment. When the order wasn't worn, a ribbon could be worn in its stead on the ribbon bar on the left side of the chest. The ribbon of the Order of the red Star was a 24mm wide silk moiré dark red with a 5mm wide central silver stripe.

Question: what flag is red and has a gold star?
Answer: flag of Vietnam.
Vietnam.
The flag of Vietnam.