利用C++如何编程：设计一个函数，判断整数n是否为素数。

N = 101 DO WHILE N <= 199 IF N MOD 3 = 0 OR N MOD 5 = 0 THEN N = N + 2 ELSE K = INT ( SQR ( N ) ) I = 2 FLAG = 0 WHILE I <= K AND FLAG = 0 IF N MOD I = 0 THEN FLAG = 1 ELSE I = I + 1 WE