最适合freshman的Java习题集

Posted 2022-01-18 王嘻嘻-

1. 求一个整数，在内存当中存储时，二进制1的个数。
2. 获取一个数二进制序列中所有的偶数位和奇数位， 分别输出二进制序列
3. 年龄打印
4. 输出乘法口诀表
5.  打印X图形

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1.求一个整数，在内存当中存储时，二进制1的个数。

import java.util.Scanner;

public class practice 
    public static void main(String[] args) 
        Scanner scanner = new Scanner(System.in);
        System.out.print("Please Enter A Num: ");
        int num = scanner.nextInt();
        int count = 0;
        while (num!=0)
            if ((num&1)==1)
                count++;
            
            num>>=1;
        
        System.out.println("共计其二进制1的个数为"+count+"个");
    

2.获取一个数二进制序列中所有的偶数位和奇数位， 分别输出二进制序列

import java.util.Scanner;

public class practice 
    public static void main(String[] args) 
        //获取一个数二进制序列中所有的偶数位和奇数位， 分别输出二进制序列
        Scanner scanner = new Scanner(System.in);
        System.out.println("Please Enter A Num:");
        int num = scanner.nextInt();
        System.out.println("偶数序列：");
        for (int i = 31; i >= 0; i-=2) 
            System.out.print((num>>i)&1);
        
        System.out.println("");
        System.out.println("奇数序列：");
        for (int i = 30; i >= 0; i-=2) 
            System.out.print((num>>i)&1);
        
    

3.年龄打印

import java.util.Scanner;

public class practice 
    public static void main(String[] args) 
        //根据输入的年龄
        // 打印出当前年龄的人是少年(低于18),
        // 青年(19-28), 中年(29-55), 老年(56以上)
        Scanner scanner = new Scanner(System.in);
        System.out.println("Please Enter A num: ");
        int age = scanner.nextInt();
        if (age <= 18)
            System.out.println("少年");
        
        if (age >= 19 && age <= 28)
            System.out.println("青年");
        
        if (age >= 29 && age <= 55)
            System.out.println("中年");
        
        if (age >= 56)
            System.out.println("老年");
        
   

4.输出乘法口诀表 

 

import java.util.Scanner;

public class practice 
    public static void main(String[] args) 
        //输出乘法口诀表
        System.out.println("Please Enter A Num : ");
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        for (int i = 1; i <= n; i++) 
            //外层循环控制行数
            for (int j = 1; j <= i; j++) 
                //内层循环控制每一行表达式的个数
                System.out.print(j+"*"+i+"="+i*j+" ");
            
            System.out.println();
        
    

  5.打印X图形

 链接👉 X形图案_牛客题霸_牛客网

import java.util.Scanner;

public class Main 
    public static void main(String[] args) 

        Scanner sc = new Scanner(System.in);
        while(sc.hasNextInt()) 
            int n = sc.nextInt();
            for(int i = 0 ; i < n ; i++) 
                for(int j = 0 ; j < n ; j++)  // 对角线 \\
                    if(i == j || i + j == n-1)  //对角线 /
                        System.out.print("*");
                     else 
                        System.out.print(" ");
                    
                
                System.out.println();