基础编程题-5

2017/05/17

题目13：一个整数，它加上100后是一个完全平方数，再加上168又是一个完全平方数，请问该数是多少？

分析
 注意如何判断一个数是完全平方数的
解答

public class chapter13 {
    public static void main(String[] args) {
        for (int i = 1;  ; i++) {
            if(get_result(i+100)&&get_result(i+168)){
                System.out.println(i);
                break;
            }
        }
    }
    private static boolean get_result(int i) {
        boolean flag = false;
        double a = Math.pow(i,1/2);
        for (int j = 1; j < Math.sqrt(i)+1; j++) {
            if(i == Math.pow(j,2)){
                flag = true;
                break;
            }
        }
        return flag;
    }
}

结果：

156

心得
 无

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题目14：输入某年某月某日，判断这一天是这一年的第几天？

分析
 注意判断闰年
解答

public class chapter14 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Please input the year:");
        int year = input.nextInt();
        System.out.println("Please input the month:");
        int month = input.nextInt();
        System.out.println("Please input the day:");
        int day = input.nextInt();
        if(month>12||month<1||day<1||day>31){
            System.out.println("Input Error");
            System.exit(0);
        }
        int number_day_of_year = get_day(year,month,day);
        System.out.println(number_day_of_year);
    }
    private static int get_day(int year, int month, int date) {
        int n = 0;
        int[] month_date = new int[] {0,31,28,31,30,31,30,31,31,30,31,30};
        if((year%400)==0 || ((year%4)==0)&&((year%100)!=0))
            month_date[2] = 29;
        for(int i=0;i<month;i++)
            n += month_date[i];
        return n+date;
    }
}

结果：

Please input the year:
2014
Please input the month:
1
Please input the day:
5
5

心得
 还可以用calendar实现。
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题目15：输入三个整数x,y,z，请把这三个数由小到大输出。

分析
 简单
解答

public class chapter15 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Please input three numbers:");
        int min = input.nextInt();
        int mid = input.nextInt();
        int max = input.nextInt();
        min = (min>mid)?(min+mid-(mid = min)):min;
        max = (max>mid)?max:(max+mid-(mid = max));
        min = (min>mid)?(min+mid-(mid = min)):min;
        System.out.println("这三个数有小到大输出为："+min+" "+mid+" "+max);
    }

结果：

Please input three numbers:
58
63
59
这三个数有小到大输出为：58 59 63

心得
 技巧