26.6.23二维数组

二维数组

public class java03_Object{
public static void main(String[] args){
//TODO常见类和对象
int[]nums=new int[3];
//num[0]=1;
for(int num:nums){
System.out.println(num);
}

}
}

2. ```java
public class java03_Object{
    public static void main(String[] args){
//TODO常见类和对象
String[]names={"yy","xx"};
    System.out.println(names); 
    for(String name:names){//names.for
     System.out.println(name); 
}
 System.out.println(names.length);
}
}

public class java03_Object{
public static void main(String[] args){
//TODO常见类和对象
String[][]namess=new String[3][3];
namess[0][1]="yy"
System.out.println(namess[0][1]);
for(int row=0;row<3;row++){
for(int col=0;col<3;col++){
System.out.print(namess[row][col]);
}
System.out.println(namess[row][col]+" ");
}
System.out.println(namess.length);
}
}

4. 九层妖塔

5. ```java
public class java03_Object{
    public static void main(String[] args){
int row=9;
int col=2*(row-1)+1;
String[][]nineTower=new String[row][col];
for(int i=0;i<row;i++){
    for(int j=0;j<col;j++){
if(j>=(row-1)-i&&j<=(row-1)+i){
    nineTower[i][j]="*";
}else{
       nineTower[i][j]=" ";
}
}
}
for(int i=0;i<row;i++){
    for(int j=0;j<col;j++){
   System.out.print(nineTower[i][j]);
}
 System.out.println();
}
}
}

public class java03_Object{
public static void main(String[] args){
//冒泡排序
int[]nums={1,4,3,5,2};
for(int num:nums){
System.out.println(num)
}
//TODO希望获取1，2，3，4，5
for(int j=0;j<nums.length;j++){
for(int i=0;i<nums.length-1;i++){
int num1=nums[i];
int num2=nums[i+1];
if(num1>num2){
nums[i]=num2;
nums[i+1]=num1;
}
}
}
for(int num:nums){
System.out.println(num)
}
}
}

7. 选择排序

8. ```java
public class java03_Object{
    public static void main(String[] args){
int[]nums={1,4,3,5,2};
for(int j=0;j<nums.length;j++){
    int maxIndex=0;
for(int i=1;i<nums.length-j;i++){
    if(nums[i]>nums[maxindex]){
    maxindex=i;
}
}
int num1=nums[nums.length-1];
int nums2=nums[maxindex];
nums[nums.length-j-1]=num2;
nums[maxindex]=num1;
}

for(int num:nums){
    System.out.println(num)
}
}
}

9. 二分查找

public class java03_Object{
public static void main(String[] args){
int[]nums={1,2,3,4,5,6,7};
int targetNum=5;
int strat=0;
int end=nums.length-1;
int middle=0;
while(start<=end){
middle=(start+end)/2;
if(nums[middle]>targetNum){
end=middle-1;
}else if(nums[middle]<targetNum){
start=middle+1;
}else{
braek;
}
}
System.out.println("数据在数组的位置："+middle);
}
}