选取随机冰淇凌例子

 

private static Random rand = new Random(); private static final String[] flavors ={"草莓","奶油","巧克力","蓝莓","香蕉","西瓜","苹果","橘子","葡萄","木瓜"}; public static String[] flavorset(int n){ if(n>10){ n = flavors.length; } String[] results = new String[n]; boolean[] picked = new boolean[flavors.length]; for(int i = 0; i<n; i++){ int t; do t = rand.nextInt(flavors.length); while(picked[t]); results[i] = flavors[t]; picked[t] = true; } return results; } public static void main (String[] args){ String[] s = flavorset(20); for(String ss:s){ System.out.println("ss ->"+ss); } }

 

以上代码,灵活的运用do while 循环特性(先执行,后判断),去除随机取出重复的"口味".

此程序方式,用途广泛,如 扑克牌游戏,简单组合问题.缺点:每次需要自行判断取出重复问题.如果能有直接取出不重复随机数的方法更为方便(继续调查).

否则,我会这么写

while(true){ t = rand.nextInt(flavors.length); if(!picked[t]){ results[i] = flavors[t]; picked[t] = true; break; } }