第七章 数组

1，逆序输出语句

public class Sentencs {
    public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
  String num[]=new String[5];  //把输出语句保存到一个数组
  System.out.println("请输入5句话");
  System.out.print("第一句话：");
      num[0]=input.next();
  System.out.print("第二句话：");
     num[1]=input.next();
     System.out.print("第三句话：");
     num[2]=input.next();
  System.out.print("第四句话：");
     num[3]=input.next();
     System.out.print("第五句话：");
     num[4]=input.next();
     System.out.println("逆序输出4句话为：");
  for(int i =num.length-1;i>=0;i--) {
   
   System.out.println(num[i]);
  }
 }
}

2，找出数组下标

public class Num {
 public static void main(String[] args) {
  int score[]= {18,25,7,36,13,2,89,63};
  Arrays.sort(score);
        System.out.println("最低积分是："+score[0]); //下标最低即为最低值
        int index=Arrays.binarySearch(score, 2);  //找出数组中某个数值下标
     System.out.println("下标是："+index);
    }

 }
 
 

3，数组分类数字

public class Number {
 public static void main(String[] args) {
  Scanner input=new Scanner(System.in);
  int nums[]=new int[10];  //数组长度
     int count[]=new int[4];  //数组种类
  System.out.println("请输入10个数：");
  for(int i =0;i<nums.length;i++) {
   nums[i]=input.nextInt();
   switch(nums[i]) {   //选择存放数组位置
   case 1:
    count[0]++;
    break;
   case 2:
    count[1]++;
    break;
   case 3:
    count[2]++;
    break;
   default:
    count[3]++;
    break;
   }
  }
  System.out.println("数字1的个数："+count[0]);
  System.out.println("数字2的个数："+count[1]);
  System.out.println("数字3的个数："+count[2]);
  System.out.println("非法数字的个数："+count[3]);
 }

}

4，数组逆序及重新赋值

public class Arrays {
    public static void main(String[] args) {
  int array[]= {1,3,-1,5,-2};
  System.out.println("原数组为：");
  for(int i=0;i<array.length;i++) {  //打印数组
   System.out.print(array[i]+"\t");
  }
  System.out.println("\n逆序处理后的数组为：");
  for(int i =array.length-1;i>=0;i--) {
   if(array[i]<0) {
    array[i]=0;   //如果数组中的值小于0赋值为0
   }
   System.out.print(array[i]+"\t");
  }
  
 }
}

5，输出并插入英文按首字母排序

public class MusicName{
 
  public static void main(String[] args) { 


    Scanner input=new Scanner(System.in); 


    String[] musics=new String[]{"Island","Ocean","Pretty","Sun"}; 


    String[] nummusics=new String[musics.length+1]; //新数组长度为原数组加1


    int index=0; //初始化插入数值下标


    String music=""; 


    System.out.print("插入前的数组:"); //打印原数组


    for(int i=0;i<musics.length;i++){ 


     nummusics[i]=musics[i];


    } 


    for(int i=0;i<musics.length;i++){ 


     System.out.print(musics[i]+" ");
    } 


    System.out.println(""); 


    System.out.print("请输入新的单词"); 


    music=input.nextLine(); 


    System.out.print("插入前新单词的下标:"); 


    for(int i=0;i<nummusics.length;i++){ //寻找新数值下标


     if(nummusics[i].compareTo(music)>0){ 


      index=i; 


      break; 


     } 


    } 


    System.out.println(index); 


    for(int i=nummusics.length-1;i>index;i--){ //元素后移


     nummusics[i]=nummusics[i-1]; 


    } 


    nummusics[index]=music; 


    System.out.print("插入后的数组:"); 


    for(int i=0;i<nummusics.length;i++){ 


     System.out.print(nummusics[i]+" ");   


    } 


   } 

  }