Java数组作业

//输入一组数（10个），找出最大值，并给出最大值的位置
package test;

public class test1_1 {
    public static double max(double []a){
      double m=a[0];
      for(int i=0;i<a.length;++i){
        if(a[i]>m){
          m=a[i];
        }
      }
      return m;
    }
    public static int pos(double []a){
      double m=a[0];
      int t=0;
      for(int i=0;i<a.length;++i){
        if(a[i]>m){
          m=a[i];
          t=i;
        }
      }
      return t;
    }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
       double a[]={1,2,3,4,5,6,7,8,9,10};
       double m;
       int n;
       m=max(a);
       n=pos(a)+1;
       System.out.println("这组数中最大数为："+m+"其位置为第"+n+"个");
  }

}
//产生10个整数放到数组中，将其顺序颠倒后输出
package test;

import java.util.Scanner;

public class test1_2 {
  public static void diandao(int[] a) {
    for (int i = 0; i < a.length / 2; ++i) {
      int t = a[i];
      a[i] = a[a.length - 1 - i];
      a[a.length - 1 - i] = t;
    }
    for (int i = 0; i < a.length; ++i) {
      System.out.print(a[i] + " ");
    }
  }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    int[] a = new int[10];
    System.out.println("请输入十个整数");
    Scanner in = new Scanner(System.in);
    for (int i = 0; i < a.length; ++i) {
      a[i] = in.nextInt();
    }
    System.out.println("原始数据为：");
    for (int i = 0; i < a.length; ++i) {
      System.out.print(a[i] + " ");
    }
    System.out.println();
    System.out.println("顺序颠倒后的数据为：");
    diandao(a);
  }

}
//产生10个整数放到数组中，将其顺序颠倒后输出
package test;

import java.util.Scanner;

public class test1_2 {
  public static void diandao(int[] a) {
    for (int i = 0; i < a.length / 2; ++i) {
      int t = a[i];
      a[i] = a[a.length - 1 - i];
      a[a.length - 1 - i] = t;
    }
    for (int i = 0; i < a.length; ++i) {
      System.out.print(a[i] + " ");
    }
  }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    int[] a = new int[10];
    System.out.println("请输入十个整数");
    Scanner in = new Scanner(System.in);
    for (int i = 0; i < a.length; ++i) {
      a[i] = in.nextInt();
    }
    System.out.println("原始数据为：");
    for (int i = 0; i < a.length; ++i) {
      System.out.print(a[i] + " ");
    }
    System.out.println();
    System.out.println("顺序颠倒后的数据为：");
    diandao(a);
  }

}
//定义一个数组，输出数组中高于平均值的元素
package test;

public class test1_4 {
    public static double avg(double []a){//求平均值
      int sum=0;
      double avg=0;
      for(int i=0;i<a.length;++i){
        sum+=a[i];
      }
      avg=sum/a.length;
      return avg;
    }
    public static String mavg(double []a){//求大于平均值的元素
      double n=avg(a);
      double m=a[0];
      String z="";
        for(int i=0;i<a.length;++i){
          if(a[i]>n){
            m=a[i];
            z=z+m+" ";
          }
        }
        return z;
    }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
     double[]a={1,2,3,4,5,6,7,8,9,0};
     System.out.println("大于平均值的元素有："+mavg(a));
  }

}
//分别形成下面两组数并输出
// 1 0 0        
// 0 1 0
// 0 0 1
//6
//11 12
//16 17 18
//21 22 23 24
//26 27 28 29 30
package test;

public class test1_6 {
  public static void fun1() {
    int[][] a = new int[3][3];
    int count = 0;
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j < a[i].length; ++j) {
        a[i][j] = 0;
        a[i][i] = 1;
        count++;
        System.out.print(a[i][j] + " ");
        if (count % 3 == 0) {
          System.out.println();
        }
      }

    }
  }

  public static void fun2() {
    int[][] a = new int[5][5];
    a[0][0]=6;
    for(int i=0;i<a.length-1;++i) {//使数组的第一列都加5
        a[i+1][0]=a[i][0]+5;
      }
    for (int i = 1; i < a.length; ++i) {
      for (int j = 1; j <= i; ++j) {
        a[i][j] = a[i - 1][j - 1] + a[0][0];
      }
    }
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j <= i; ++j) {
        System.out.print(a[i][j] + " ");
      }
      System.out.println();
    }
  }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
    fun1();
    fun2();
  }

}
//求二维数组中,最大元素及其所在的行和列的位置
package test;

public class test1_7 {
  public static void max(int[][] a) {
    int h = 0, l = 0;
    int max = a[0][0];
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j < a[i].length; ++j) {
        if (a[i][j] > max) {
          max = a[i][j];
          h = i+1;
          l = j+1;
        }
      }
    }
    System.out.println("该数组最大元素为:" + max + "在第" + h + "行" + "第" + l + "列");
  }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    int[][] a = new int[3][3];
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j < a[i].length; ++j) {
        a[i][j] = (int) (Math.random() * 100);
      }
    }
    System.out.println("随机产生的一个二维数组为:");
    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();
    }
    max(a);
  }

}
//将一个二维数组行和列元素互换.存到另一个二维数组
package test;

public class test1_8 {
  public static int[][] huhuan(int[][] a) {
    int[][] b = new int[3][3];
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j < a[i].length; ++j) {
        b[j][i] = a[i][j];
      }
    }
    /*
     * System.out.println("交换后的数组为:"); for (int j = 0; j < b.length; ++j) { for (int
     * i = 0; i < b[j].length; ++i) { System.out.print(b[j][i] + " "); }
     * System.out.println(); }
     */
    return b;
  }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    int[][] a = new int[3][3];
    for (int i = 0; i < a.length; ++i) {
      for (int j = 0; j < a[i].length; ++j) {
        a[i][j] = (int) (Math.random() * 100);
      }
    }
    System.out.println("随机产生的一个二维数组为:");
    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();
    }
    int[][] b = huhuan(a);
    System.out.println("交换后的数组为:");
    for (int j = 0; j < b.length; ++j) {
      for (int i = 0; i < b[j].length; ++i) {
        System.out.print(b[j][i] + " ");
      }
      System.out.println();
    }
  }

}
//设计程序,生成杨辉三角形(利用数组)
package test;

public class test1_9 {
  public static int [][] yanghui(int [][]a){
      for(int i=0;i<a.length;++i) {//使数组的第一列都为1
        a[i][0]=a[i][i]=1;
      }
      for(int i=1;i<10;++i) {
        for(int j=1;j<=i;++j) {
          a[i][j]=a[i-1][j]+a[i-1][j-1];
        }
      }
      return a;
    }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
       int [][]a=new int[10][10];
           for(int i=0;i<a.length;++i) {//初始化数组
              for(int j=0;j<a[i].length;++j) {
                a[i][j]=0;
              }
            }
       int [][]b=yanghui(a);
       for(int i=0;i<b.length;++i) {
         for(int j=0;j<=i;++j) {
           System.out.print(b[i][j]+" ");
         }
         System.out.println();
       }
  }

}
//输入十个数,按照升序排序,并输出排序结果
package test;

import java.util.Arrays;
import java.util.Scanner;

public class test2_1 {
    public static int [] sort(int []a){
       /*for (int i = 0; i < a.length; i++) {
             for (int j = i + 1; j < a.length; j++) {
             if (a[i] > a[j]) {
                    int temp = a[i];
                        a[i] = a[j];
                    a[j] = temp;
                }
            }
        }*/
      for(int i=0;i<a.length-1;++i) {
        int min=i;
        for(int j=i+1;j<a.length;++j) {
          if(a[j]<a[min]) {
            min=j;
          }
        }
        if(i!=min) {
          int t=a[i];
          a[i]=a[min];
          a[min]=t;
        }
      }
      return a;
    }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
        int []a=new int[10];
        //int b[]= {1,0,9,8,7,6,5,4,3,2,};
        //Arrays.sort(b);//更快
        for(int i=0;i<a.length;++i) {
          Scanner in=new Scanner(System.in);
          a[i]=in.nextInt();
        }
        System.out.println("排序前的数据为");
        for(int i=0;i<a.length;++i) {
          System.out.print(a[i]+" ");
        }
        System.out.println();
        int []b=sort(a);
        System.out.println("排序后的数据为");
        for(int i=0;i<b.length;++i) {
          System.out.print(b[i]+" ");
        }
        
  }

}
//有n个数据,存放在数组a中,现输入一个数据x,在数组a中查找数据x是否存在,如果存在
//则输出第一次出现的位置号,否则,输出-1
package test;

import java.util.Scanner;

public class test2_2 {
    public static int find(int []a,int x) {
        int t=0;
      for(int i=0;i<a.length;++i) {
          if(x==a[i]) {
             t=i;
             break;
          }
          else
          {
             t=-1;
          }
        }
        return t;
    }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
       int []a= {1,2,3,4,5,6,7,8,9,0};
       int x;
       Scanner in=new Scanner(System.in);
       System.out.println("请输入要查找的数:");
       x=in.nextInt();
       System.out.println("要查找的数据的位置为:"+find(a, x));
  }

}
//有n个数据,存放在数组a中,现输入一个数据x,要在数组a中y数据第一次出现的位置后
//插入数据x,如果y在数组a中,则将x插入到数组a的首位置
package test;

import java.util.Scanner;

public class test2_3 {
  public static int find(int []a,int x) {//查找数据y
        int t=0;
      for(int i=0;i<a.length;++i) {
          if(x==a[i]) {
             t=i;
             break;
          }
          else
          {
             t=-1;
          }
        }
        return t;
    }
  public static int [] insert(int []a,int y,int x) {//插入数据
    int p=find(a, y);
        if(p==-1)
        {
          for(int i=a.length-2;i>=0;--i) {
            a[i+1]=a[i];
          }
          a[0]=x;
        }
        else
        {
          for(int i=a.length-2;i>=p+1;--i) {
            a[i+1]=a[i];
          }
          a[p+1]=x;
        }
        return a;
  }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
     int[]a=new int[11];
       for(int i=0;i<a.length-1;++i)//初始化数组
       {
         a[i]=i;
       }
       System.out.println("初始化数据为:");
         for(int e:a) {//增强for语句
           System.out.print(e+" ");
         }
         System.out.println();
       System.out.println("请输入要在哪个元素后插入和插入的数据元素为:");
       Scanner in=new Scanner(System.in);
       int y=in.nextInt();
       int x=in.nextInt();   
       int []b=insert(a,y,x);
       System.out.println("插入后的数据元素为:");
       for(int i=0;i<b.length;++i) {
         System.out.print(b[i]+" ");
       }
  }

}
//同上题将x插入到y之前
package test;

import java.util.Scanner;

public class test2_4 {
  public static int find(int []a,int x) {//查找数据y
        int t=0;
      for(int i=0;i<a.length;++i) {
          if(x==a[i]) {
             t=i;
             break;
          }
          else
          {
             t=-1;
          }
        }
        return t;
    }
  public static int [] insert(int []a,int y,int x) {//插入数据
    int p=find(a, y);
        if(p==-1)
        {
          for(int i=a.length-2;i>=0;--i) {
            a[i+1]=a[i];
          }
          a[0]=x;
        }
        else
        {
          for(int i=a.length-2;i>=p-1;--i) {
            a[i+1]=a[i];
          }
          a[p]=x;
        }
        return a;
  }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
     int[]a=new int[11];
       for(int i=0;i<a.length-1;++i)//初始化数组
       {
         a[i]=i;
       }
       System.out.println("初始化数据为:");
    for(int e:a) {//增强for语句
      System.out.print(e+" ");
    }
    System.out.println();
       System.out.println("请输入要在哪个元素前插入和插入的数据元素为:");
       Scanner in=new Scanner(System.in);
       int y=in.nextInt();
       int x=in.nextInt();   
       int []b=insert(a,y,x);
       System.out.println("插入后的数据元素为:");
       for(int i=0;i<b.length;++i) {
         System.out.print(b[i]+" ");
       }
  }

}
//有n个数据,存放在数组a中,现输入一个数据x,要在数组a中删除第一次出现的x
package test;

import java.util.Scanner;

public class test2_5 {
  //删除全部x
  /*public static void dele(int []a,int x) {
    for(int i=0;i<a.length;++i) {
      if(a[i]==x)
      {
        a[i]=666;
      }
    }
    for(int i=0;i<a.length;++i) {
      if(a[i]!=666) {
        System.out.print(a[i]+" ");
      }
    }
    
  }*/
  //删除第一个x
  public static int find(int[] a, int x) {// 查找数据x
    int t = 0;
    for (int i = 0; i < a.length; ++i) {
      if (x == a[i]) {
        t = i;
        break;
      } else {
        t = -1;
      }
    }
    return t;
  }

  public static int[] dele(int[] a, int x) {
    int d = find(a, x);
    int []b=new int[a.length-1];
    for(int i=0;i<d;++i) {
      b[i]=a[i];
    }
    for (int i = d; i < a.length-1; ++i) {
      b[i] = a[i + 1];
    }
    return b;
  }

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    int[] a = new int[10];
    for (int i = 0; i < a.length; ++i)// 初始化数组
    {
      a[i] = i;
    }
    System.out.println("初始化数据为:");
    for(int e:a) {//增强for语句
      System.out.print(e+" ");
    }
    System.out.println();
    System.out.println("请输入要删除的数据元素为:");
    Scanner in = new Scanner(System.in);
    int x = in.nextInt();
    int[] b = dele(a, x);
    //dele(a,x)
    System.out.println("删除后的数据元素为:");
    for (int i = 0; i < b.length; ++i) {
      System.out.print(b[i] + " ");
    }
  }
}
//输入10个数,并按照由小到大排序输出,然后再输入一个数据
//插入到已排好序中,插入后仍然是由小到大排序
package test;

import java.util.Arrays;
import java.util.Scanner;

public class test2_6 {
    public static int[] fun(int []a,int x) {
      int []b=new int[a.length+1];
      b[a.length]=x;
      for(int i=0;i<a.length;++i) {
        b[i]=a[i];
      }
      Arrays.sort(b);
      return b;
    }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
    Scanner in = new Scanner(System.in);
    System.out.println("请输入10个数:");
    int []a=new int[10];
    for(int i=0;i<a.length;++i) {
          a[i]=in.nextInt();
        }
    System.out.println("排序后的十个数为:");
    Arrays.sort(a);//排序
    for (int i = 0; i < a.length; ++i) {
      System.out.print(a[i] + " ");
    }
    System.out.println();
    System.out.println("插入x");
    int x = in.nextInt();
    int[] b = fun(a,x);
    System.out.println("排序后的十一个数为:");
    for (int i = 0; i < b.length; ++i) {
      System.out.print(b[i] + " ");
    }
  }

}