public class Test {
public static void main(String[] args) {
makeShape(14);
}
public static void makeShape(int needLength) {
if (needLength > 30) {
System.out.println("不要太过分!日");
return;
}
for (int i = 0; i < needLength; i++) {
for (int j = i; j < needLength-1; j++) {
System.out.print(" ");
}
for (int j = 0; i >= j; j++) {
System.out.print("* ");
}
System.out.println();
}
for (int i = 0; i < needLength; i++) {
for (int j = 0; i >= j; j++) {
System.out.print(" ");
}
for (int j = i; j < needLength-1; j++) {
System.out.print("* ");
}
System.out.println();
}
}
private int x = 100; // 成员变量 / 属性 / 字段 指的都是它 名字好几个呢
// 叫函数的是它 叫方法的也是它
public void 呵呵() {
int xx = x; // 这里的xx 叫 局部变量 , 必须初始化值 什么叫初始化? 你就理解给它个默认值
System.out.println(xx);
}
public void hehe() {
}
public Test() {
System.out.println("无参构造函数");
}
public Test(int x) {
System.out.println(x);
System.out.println("有参构造函数1");
}
public Test(int x, int y, int z) {
System.out.println(x + "" + y + "" + z);
System.out.println("有参构造函数2");
}
public Test(int x, int y) {
System.out.println(x + "--" + y);
System.out.println("有参构造函数3");
}
}
/**
* 单例 1
*
* @Description:饿汉
*/
class Single01 { // 不能被public修饰 public class Single01 是错误的
private Single01() {
}
private static Single01 single = new Single01();
public static Single01 getInstance() {
return single;
}
}
/**
* 单例 2
*
* @Description:懒汉
*/
class Single02 { // 不能被public修饰 public class Single02 是错误的
private Single02() {
}
private static Single02 single = null;
public static Single02 getInstance() {
if (single == null) {
single = new Single02();
}
return single;
}
} |