说明：  编制函数prime，用来判断整数n是否为素数：bool prime(int n)； 而后编制主函数，任意输入一个大于4的偶数n，找出满足n=i+j的所有数对，其中要求i与j均为素数（通过调用prime来判断素数）。如偶数18可以分解为11+7以及13+5；而偶数80可以分解为：43+37、61+19、67+13、73+7。
(establishment prime function, used to judge whether the integer n is prime : bool prime (int n); Then prepare the main function, indiscriminate importation of a greater than even the 4 n, identify meet n = i j few all right, which called i and j are prime (by calling the prime to determine prime numbers). If even 18 can be decomposed to 11 7 and 13 5; And even 80 can be decomposed as follows : 19 43 37,61, 67 13,73 7.)