java练习

import java.util.Scanner;

public class Test01 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
pw(sc);

}
// 三次密码验证
public static void pw(Scanner sc){
boolean zh = false;
boolean pw = false;
int i = 3;
while(i >0){
System.out.println("您还有"+i+"次输入机会");
System.out.println("请输入您的用户名");
zh = sc.next().equals("admin");
System.out.println("请输入您的密码");
pw = sc.next().equals("20191225");
i--;
if(zh&&pw)
break;
}
if(zh&&pw == true){
zt(sc);
}
}
// 系统主体界面
public static void zt(Scanner sc){
String y = null;
do {
System.out.println("-------------欢迎admin进入系统-------------");
System.out.println("1.计算梯形面积");
System.out.println("2.求指定范围的素数");
System.out.println("3.打印菱形");
System.out.println("4.求指定范围的水仙花数");
System.out.println("0.安全退出系统");
System.out.println("---------@copyRight 2019-12-24 v1.0 高新管HP1904班所有---------");
System.out.println("请输入您要选择的序号：");
int a = sc.nextInt();
if (a == 1) {
mj(sc);
}else if(a == 2){
ss(sc);
}else if (a ==3) {
lx(sc);
}else if (a == 4) {
sxhs(sc);
}else if(a == 0){
System.out.println("您已选择退出，立即退出系统");
break;
}else{
System.out.println("您的选择有误，请返回重新选择");
}
System.out.println("返回主菜单请按“Y”或者“y”");
y = sc.next();

} while (y.equals("Y")||y.equals("y"));
}
// 梯形的面积
public static void mj(Scanner sc){
// 梯形面积公式= （a+c）*h/2
System.out.println("请输入您的上底");
int a = sc.nextInt();
System.out.println("请输入您的下底");
int c = sc.nextInt();
System.out.println("请输入您的高");
int h = sc.nextInt();
System.out.println("您梯形的面积是："+(a+c)*h/2);
}
// 指定范围的素数
public static void ss(Scanner sc){

}
// 菱形
public static void lx(Scanner sc){
System.out.println("请输入菱形的行数");
int arr =sc.nextInt();
if(arr%2 == 0){
System.out.println("您输入的是一个偶数，请重新选择");
}else{
int a = arr/2+1;
for (int i = 0; i < a; i++) {
for (int j = 0; j < a-i; j++) {
System.out.print(" ");
}
for (int j = 0; j < i; j++) {
System.out.print("* ");
}
System.out.println();
}
for (int i = 0; i < a; i++) {
for (int j = 0; j < i; j++) {
System.out.print(" ");
}
for (int j = 0; j < a-i; j++) {
System.out.print("* ");
}
System.out.println();
}
}
}
// 水仙花数
public static void sxhs(Scanner sc){
System.out.println("开始");
int a = sc.nextInt();
System.out.println("结束");
int b = sc.nextInt();
for (int i = a; i <= b; i++) {
int gewei = i%10;
int shiwei =i/10%10;
int baiwei = i/100%10;
int c = gewei*gewei*gewei+shiwei*shiwei*shiwei+baiwei*baiwei*baiwei;
if(c == i){
System.out.println(i+"是水仙花数");
}
}
}
}

java练习

原文：https://www.cnblogs.com/weixin2623670713/p/13322053.html