Java 编程求大佬解答
public static void main(String[] args) {// 定义主方法
System.out.println("欢迎您的到来");// 欢迎用户
System.out.println("请设置您的密码");// 提示客户设置密码
Scanner a = new Scanner(System.in);// 输入密码
String sa = a.next();// 将Scanner型数据a转换为String型数据sa
System.out.println("恭喜您,设置成功!");// 提示用户设置成功
System.out.println("请再次确认,您的密码是:" + sa);// 用户再次确认密码
byte c = 4;// 定义变量c
xa: while (c > 0) {// 定义while循环语句xa
System.out.println("现在,请输入您的密码:");// 提示用户输入密码
Scanner b = new Scanner(System.in);// 输入密码
String sb = b.next();// 将Scanner型数据a转换为String型数据sb
if (!sa.equals(sb)) {// 如果sa不等于sb(密码错误),运行下列语句
c--;// 对c进行自减(减1)
System.out.println("对不起,密码错误。请重新输入,您还剩" + c + "次机会");
continue xa;
} // 提示用户密码正确
else {// 如果sa等于sb(密码正确),运行下列语句
System.out.println("恭喜您,密码正确!"); // 提示用户密码错误及所剩输入机会
}
}
}
//Circle类
public class Circle{
double radius;
double area;
double circumference;
public void setCircle(double radi){
if(radi>0){
radius=radi;
}else{
System.out.println("半径必须大于0");
}
}
public void calArea(){
if(radius>0){
area=Math.PI* Math.pow(radius,2);
}
}
public void calCircumference(){
if(radius>0){
circumference=2*Math.PI* radius;
}
}
}
//测试类
public class Test{
public static void main(String[] args) {
Circle[] circleArray=new Circle[5];
int size=circleArray.size();
double totalArea;
for(int i=0;i<size;i++){
circleArray[i].setCircle(i);
}
for(int i=0;i<size;i++){
totalArea+=circleArray[i].calArea();
}
System.out.println("5个圆的面积和为"+totalArea);
}
}
import java.util.*;
class Test {
public static String get(String v) {
String reg2 = "^[a-zA-Z_\\$]\\w*$";
String[] keywords = {
"abstract", "assert", "boolean", "break", "byte", "case", "catch", "char", "class", "const", "continue", "default", "do", "double", "else", "enum", "extends", "final", "finally", "float", "for", "if", "implements", "import", "instanceof", "int", "interface", "long", "native", "new", "package", "private", "protected", "public", "return", "short", "static", "strictfp", "super", "switch", "synchronized", "this", "throw", "throws", "generic", "transient", "try", "void", "volatile", "while", "byValue", "cast", "false", "future", "inner", "operator", "outer", "rest", "true", "var", "goto", "const", "null"
};
String regex = "(" + Arrays.toString(keywords).replaceAll("[\\[\\]\\s]", "").replaceAll("\\,", "|") + ")";
String reg3 = "^[a-z][a-zA-Z\\d]*";
if (!v.matches(regex)) {
if (v.matches(reg3)) {
return "专业";
} else if (v.matches(reg2)) {
return "合法, 或使用较差的样式";
}
} else {
return "非法";
}
return null;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System. in );
while (true) {
String w = sc.nextLine();
if ("q".equals(w)) {
sc.close();
break;
}
System.out.println(get(w));
}
}
}
这个最简单的就可以用到正则表达式了