LogicalJava_Test

​1、控制台输入月份，输出该月为第几季度？

int month = 12;
int quarter = (month-1)/3+1;
System.out.println(quarter);

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2、控制台输入年、月、日，输出该日期为星期几？

public static void main(String[] args) throws Exception {
	Scanner in = new Scanner(System.in);
	System.out.print("请输入年份：");
	String year = in.next();
	System.out.print("请输入月份：");
	String month = in.next();
	System.out.print("请输入日期：");
	String day = in.next();

	SimpleDateFormat fmt = new SimpleDateFormat("dd MM yyyy");
	Date d = fmt.parse(day+" "+month+" "+year);
	Calendar cal = Calendar.getInstance();
	cal.setTime(d);
	int weekDay = cal.get(Calendar.DAY_OF_WEEK);
	switch(weekDay) {
		case 1 : System.out.println("星期日"); break;
		case 2 : System.out.println("星期一"); break;
		case 3 : System.out.println("星期二"); break;
		case 4 : System.out.println("星期三"); break;
		case 5 : System.out.println("星期四"); break;
		case 6 : System.out.println("星期五"); break;
		case 7 : System.out.println("星期六"); break;
		default: break;
	}
}

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 3、所有的2位~4位数中水仙花有几个？
    水仙花数
    2位数ab     a*a+b*b=ab
    3为数abc    a*a*a+b*b*b+c*c*c=abc
    4位数abcd    a*a*a*a+b*b*b*b+c*c*c*c+d*d*d*d=abcd

public static void main(String[] args) {
	int count = 0;

	for (int i = 10, copy, sum; i < 10000 ; i++) {
		sum = 0;
		copy = i;
		while (copy>=1){
			sum += Math.pow(copy%10, i<100 ? 2 : i<1000 ? 3 : 4);
			copy /= 10;
		}
		if(sum == i){
			count++;
			System.out.println(i);
		}
	}
	System.out.println("水仙花数有： "+count+" 个");
}

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4、随机生成5以上的奇数，并以井号输出该行数的空心菱形？

public static void main(String[] args) {
	Random random = new Random();
	int ran  = 4+random.nextInt(10) * 2 + 1;
	System.out.println("随机生成的数为"+ran);

	//空心菱形
	int num=ran/2+1;
	for (int i = 1; i <= num; i++) {
		for (int j = 1; j <= num-i ; j++) {
			System.out.print(" ");
		}
		//打印原本实心的部分
		for (int j = 1; j <=2*i-1 ; j++) {
			//仅在第一行的开头和末尾打印#
			if(j==1 ||j==2*i-1){
				System.out.print("#");
			}else {
				System.out.print(" ");
			}
		}
		System.out.println();
	}
	for (int i = num-1; i >=1 ; i--) {
		for (int j = 1; j <=num-i ; j++) {
			System.out.print(" ");
		}
		for (int j = 1; j <= 2*i; j++) {
			if (j==1 ||j==2*i-1){     //第一(斜)列全是#，然后下一个#在他们的2n-1位置处
				System.out.print("#");
			}else{
				System.out.print(" ");
			}
		}
		System.out.println();
	}
}

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5、将1000以内2位以上的整数中能分解为2个约数且约数为质数的数有多少个？分别是哪些？  

 

public class test5 {

    static int count = 0;

    public boolean isPrimeNumber(int num){
        for (int i = 2; i < num; i++,count++) {
            if (num%i==0) {
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        //将1000以内2位以上的整数中能分解为2个质数的数有多少个？分别是哪些？
        test5 lj = new test5();
        int pnNum = 0;
        for (int i = 10,k; i <= 1000; i++) {
            for (int j = 2; j <= i/2; j++) {
                if(i%j==0){
                    k=i/j;
                    if (lj.isPrimeNumber(j) && lj.isPrimeNumber(k)){
                        pnNum++;

                        System.out.println(i);
                        break;
                    }

                }
            }

        }
        System.out.println("Count:"+count);
        System.out.println("Num:"+pnNum);
    }
}
//296

public static void main(String[] args) {
	int[] num = new int[1000];
	int size = 0, count = 0;
	num[size++] = 2;
	for (int i = 3; i <= 1000; i += 2) {
		boolean is = true;
		for (int j = 0; num[j] <= Math.sqrt(i); j++) {
			if (i % num[j] == 0) {
				is = false;
				break;
			}
		}
		if (is) {
			num[size++] = i;
		}
	}
	for( int i = 0 ; i < num.length ; i++ ){
		for( int j = i+1 ; j < num.length ; j++){
			if(num[i]*num[j] >= 10 && num[i]*num[j] <= 1000){
				count++ ;
				System.out.println(num[i]*num[j]);
			}
		}
	}
	System.out.println("一共有"+ count +"个数");
}
//287

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