java--数组2

深碍√TFBOYSˉ_ 2022-08-08 11:47 157阅读 0赞

public class ArratTest \{  
public static void main(String\[\] args) \{  
Student\[\] s = new Student\[100\];  
for (int i = 0;i <s.length;i++) \{  
s\[i\] = new Student();  
if(i%2 == 0) \{  
s\[i\].name="zhangsan";  
\}  
else\{  
s\[i\].name = "lisi";  
\}  
for (int i =0;i<s.length; i++)\{  
System.out.println(s\[i\].name);  
\}  
\}  
\}  
\}  
class Student \{  
String name;  
\}  
  
  
二维数组是一种平面的二维结构，本质上是数组的数组。  
  
  
public class ArrayTest \{  
public static void main(String\[\] args) \{  
int\[\] a = new int\[4\];  
  
int\[\]\[\] a = new int\[2\]\[3\];  
i\[0\]\[0\] = 1;  
System.out.println(i\[0\] instanceof int\[\])  
\}  
\}  
int m = 0;  
for(int i = 0; i < 2 ;i++)\{  
for(int j = 0; j<3;j++)\{  
m++;  
a\[i\]\[j\] = 2\* m;  
\}  
\}  
  
  
  
  
  
  
  
  
  
  
public class ArrayTest \{  
public static void main(String\[\] args) \{  
int\[\]\[\] a = new int\[3\]\[\];  
a\[0\] = new int\[2\];  
a\[1\] = new int\[3\];  
a\[2\] = new int\[1\];  
  
  
  
  
int\[\]\[\] a = new int\[\]\[3\];//错误的语法  
  
  
int\[\] a = new int\[\]\{1,2,3\};  
  
  
int\[\]\[\] a = new int\[\]\[\]\{ \{1,2,3\},\{4\},\{5,6,7,8\}\};  
for(int i = 0;i <a.length;i++)\{  
for(int j = 0; j<a\[i\].length; j++) \{  
System.out.print(a\[i\]\[j\]+" ");  
\}  
System.out.println();  
\}  
System.out.println(a\[3\]\[4\]);  
  
\}

二维数组是一种平面的二维结构。本质上是数组的数组。  
type\[\]\[\] a = new type\[2\]\[3\];  
  
  
  
  
public class Swap\{  
public static void swap(int a, int b) \{  
int temp= a;  
a = b;  
b = temp;  
\}  
public static void main(String\[\] args)\{  
int x = 3;  
int y = 4;  
Swap.swap(x,y);  
System.out.println(x);  
System.out.println(y);//结果是3，4，赋完值并不影响xy的值  
  
  
  
  
System.out.println(\`\`\`\`\`\`\`\`\`\`\`\`\`);  
  
  
int temp = x;  
x = y ;  
y = temp;  
System.out.println(x);  
System.out.println(y);  
\}  
\}  
  
  
swap(交换)  
  
  
int a = 3;  
int b = 4;  
a = a + b;  
b = a - b;  
a = a - b;  
  
  
  
  
  
  
  
  
  
  
public class Swap \{  
public stativ void swap(char\[\] ch) \{  
ch\[0\] = 'B';  
c = 'D';  
\}  
public static void main(String\[\] args) \{  
ch\[\] ch = \{'A','C'\};  
swap(ch,ch\[1\]);  
for(int i = 0; i <ch.length:i++)\{  
System.out.println(ch\[i\]);  
\}  
\}  
  
\}  
  
  
  
  
  
  
  
  
public class ArrayTest \{  
public static void main(String\[\] args) \{  
I\[\] i = new I\[2\];//生成一个长度为2的数组,并不指向任何对象  
  
i\[0\] = new C();  
i\[1\] = new C();  
  
  
int \[\] a = new int \[\] \{1,2,3\};  
I\[\] b = new I\[\]\{new C(),new C()\};  
\}  
\}  
interface I \{//接口不能生成对象  
  
  
\}  
  
  
class C implements I \{  
  
  
\}  
  
  
  
  
  
  
java.util 帮助我们完成一些辅助功能的方法，经常定义为static  
import java.util.Arrays;  
public class ArrayTest \{  
//比较两个数组的内容是否一样  
public static boolean isEquals(int\[\] a,int\[\] b) \{  
if (a == null || b == null) \{  
return false;  
\}  
if(a.length !=b.length) \{  
return false;  
\}  
for(int i = 0; i<a.length; i++) \{  
if(a\[i\] != b\[i\]) \{  
return false;  
\}  
\}  
return true;  
\}  
public static void main(String\[\] args) \{  
int\[\] a = \{1,2,3\};  
int\[\] b = \{1,2,3\};  
System.out.println(isEquals(a,b));  
  
  
  
  
System.out.println(Arrays.eauals(a,b));  
\}  
\}  
  
  
  
public class ArrayTest \{  
public static void main(String\[\] args) \{  
int\[\] a = new int\[\] \{1,2,3\};  
int \[\] b = new int\[4\];  
System.arraycopy(a,0,b,0,4);  
for(int i = 0;i<b.lentth;i++) \{  
System.out.println(b\[i\]);  
\}  
\}  
\}  
  
  
  
  
三维数组。type\[\]\[\]\[\] a = new type\[2\]\[3\]\[4\];  
  
  
public class ArrayTest \{  
poublic static void main(String\[\] args) \{  
int \[\]\[\]\[\] a =new int\[2\]\[3\]\[4\];  
System.out.println(a instanceof int\[\]\[\]\[\]);  
System.out.println(a instanceof object);  
  
  
System.out.println(a\[0\] instanceof int\[\]\[\]);  
  
  
System.out.println(a\[0\]\[0\] instanceof int\[\]);  
  
  
for(int i = 0; i<a.length; i++) \{  
for (int j = 0;j <a\[i\].length;j++)\{  
for(int k = 0;k <a\[i\]\[j\].length;k++)\{  
a\[i\]\[j\]\[k\] = 100;  
\}  
\}  
\}  
\}  
\}