// 2的次冪
public static int check(int num) {
    if (num % 2 == 0) {
        int count = num / 2;
        if (count > 0 && count != 1) {
            count = check(count);
        }
        return count;
    }else{
        return 0;
    }
}
// 等於1即成立
public static void main(String[] args) {

System.out

}

第二種方法(二進位制更簡單)

public static boolean check(int num) {

    return num & (num - 1);

}