第六周——猜生日

问题及代码：

package chapter3;

import java.util.Scanner;

public class GuessBirthday {
  public static void main(String[] args) {
    String set1 =
      " 1  3  5  7\n" +
      " 9 11 13 15\n" +
      "17 19 21 23\n" +
      "25 27 29 31";

    String set2 =
      " 2  3  6  7\n" +
      "10 11 14 15\n" +
      "18 19 22 23\n" +
      "26 27 30 31";

    String set3 =
      " 4  5  6  7\n" +
      "12 13 14 15\n" +
      "20 21 22 23\n" +
      "28 29 30 31";

    String set4 =
      " 8  9 10 11\n" +
      "12 13 14 15\n" +
      "24 25 26 27\n" +
      "28 29 30 31";

    String set5 =
      "16 17 18 19\n" +
      "20 21 22 23\n" +
      "24 25 26 27\n" +
      "28 29 30 31";

    int day = 0;

    // Create a Scanner
    Scanner input = new Scanner(System.in);

    // Prompt the user to answer questions
    System.out.print("Is your birthday in Set1?\n");
    System.out.print(set1);
    System.out.print("\nEnter 0 for No and 1 for Yes: ");
    int answer = input.nextInt();

    if (answer == 1)
      day += 1;

    // Prompt the user to answer questions
    System.out.print("\nIs your birthday in Set2?\n");
    System.out.print(set2);
    System.out.print("\nEnter 0 for No and 1 for Yes: ");
    answer = input.nextInt();

    if (answer == 1)
      day += 2;

    // Prompt the user to answer questions
    System.out.print("Is your birthday in Set3?\n");
    System.out.print(set3);
    System.out.print("\nEnter 0 for No and 1 for Yes: ");
    answer = input.nextInt();

    if (answer == 1)
      day += 4;

    // Prompt the user to answer questions
    System.out.print("\nIs your birthday in Set4?\n");
    System.out.print(set4);
    System.out.print("\nEnter 0 for No and 1 for Yes: ");
    answer = input.nextInt();

    if (answer == 1)
      day += 8;

    // Prompt the user to answer questions
    System.out.print("\nIs your birthday in Set5?\n");
    System.out.print(set5);
    System.out.print("\nEnter 0 for No and 1 for Yes: ");
    answer = input.nextInt();

    if (answer == 1)
      day += 16;

    System.out.println("\nYour birthday is " + day + "!");
  }
}

运行结果:

Is your birthday in Set1?
 1  3  5  7
 9 11 13 15
17 19 21 23
25 27 29 31
Enter 0 for No and 1 for Yes: 
1

Is your birthday in Set2?
 2  3  6  7
10 11 14 15
18 19 22 23
26 27 30 31
Enter 0 for No and 1 for Yes: 1
Is your birthday in Set3?
 4  5  6  7
12 13 14 15
20 21 22 23
28 29 30 31
Enter 0 for No and 1 for Yes: 1

Is your birthday in Set4?
 8  9 10 11
12 13 14 15
24 25 26 27
28 29 30 31
Enter 0 for No and 1 for Yes: 1

Is your birthday in Set5?
16 17 18 19
20 21 22 23
24 25 26 27
28 29 30 31
Enter 0 for No and 1 for Yes: 1

Your birthday is 31!

知识点总结：

if语句。 string

 

心得及体会：

做这个题是因为一直理解不了这个逻辑。弄了很久才明白，玄机在这些数字里。通过奇数和偶数的排除来计算。