1. 打印出所有的"水仙花数",所谓"水仙花数"是指一个三位数,其各位数字立方和等于该数本身。例如:153是一个"水仙花数",因为153=1的三次方+5的三次方+3的三次方。(知识点:循环语句、条件语句)
package pra; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int num = 100; int g,s,b; for(num = 100;num < 1000;num++){ g = num % 10; s = num % 100 / 10; b = num / 100; if(num == g * g * g + s * s * s + b * b * b ){ System.out.println(num); } } } }
2.在控制台输出以下图形(知识点:循环语句、条件语句)
package pra; import java.util.Scanner; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub for(int i = 1; i <= 6; i++) { for(int j = 0; j < i; j++) { System.out.print(""); } for(int j = 1; j <= i; j++) { System.out.print(j); } System.out.println(); } System.out.println("--------------------"); for(int i = 6;i >= 1;i--) { for(int j = 1;j <= i;j++){ System.out.print(j); } System.out.println(); } System.out.println("--------------------"); for (int i = 1; i <= 6; i++) { for (int j = 1; j <= 7 - i; j++) { System.out.print(" "); } for (int j = i; j >= 1; j--) System.out.print(j); System.out.println(); } System.out.println(); System.out.println("---------------------"); for(int i=6;i>0;i--) { for(int k=0;k<6-i;k++) { System.out.print(" "); } for(int j = 1;j <= i;j++) { System.out.print(j); } System.out.println(); } } }
3. 输入年月日,判断这是这一年中的第几天(知识点:循环语句、条件语句)
package pra; import java.util.Scanner; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("请输入年:"); int year=input.nextInt(); System.out.println("请输入月:"); int month=input.nextInt(); System.out.println("请输入日:"); int day = input.nextInt(); int total = 0; //统计输入月份之前一共多少天 for(int i = 1;i < month;i++) { switch(i) { case 4: case 6: case 9: case 11: total += 30; break; case 2: if(year % 4== 0 && year %100 != 0 || year % 400 == 0) total += 29; else total += 28; break; default: total += 31; break; } } total += day; System.out.println("该天是第" + total + "天"); } }
4.由控制台输入一个4位整数,求将该数反转以后的数,如原数为1234,反转后的数位4321(知识点:循环语句、条件语句)
package pra; import java.util.Scanner; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("请输入一个四位数"); int n=input.nextInt(); if(n > 999 && n <= 9999) { int a = n / 1000; int b = n / 100 % 10; int c = n / 10 % 10; int d = n % 10; int s = d * 1000 + c * 100 + b * 10 + a; System.out.println("反转后数为�" + s); } else{ System.out.println("error"); } } }