正文  电脑教程 > 服务器教程 >

冒泡排序,二分查找法、for循环实例教程

import java.util.Arrays; //冒泡排序 public class Test { public static void ...

import java.util.Arrays;

//冒泡排序
public class Test {

  public static void main(String[] args) {
    int[] array = { 31, 22, 15, 77, 52, 32, 18, 25, 16, 7 };
    // 冒泡 --> 两两比较 --> 提取出最大的数 在最后一位 
     //拿第一位和它后面的一位进行 两两比较
    System.out.println(Arrays.toString(array));
    for (int j = 0; j < array.length; j++) {
      for (int i = 0; i < array.length - 1 - j; i++) {
        // 如果前面的数大于后面的数 交换位置
        if (array[i] < array[i + 1]) {
          int temp = array[i];
          array[i] = array[i + 1];
          array[i + 1] = temp;
        }
      }
    }
    System.out.println(Arrays.toString(array));
  }
}
import java.util.Arrays;
//选择排序
public class Test {

  public static void main(String[] args) {
    int[] array = { 31, 22, 15, 77, 52, 32, 18, 25, 16, 7 };
    // 选择 --> 第一位与后面所有的数字进行比较 
    System.out.println(Arrays.toString(array));
    for (int i = 0; i < array.length; i++) {
      for (int j = i + 1; j < array.length; j++) {
        if (array[i] < array[j]) {
          // 如果 array[0]比array[1]大,交换位置
          // 第三方变量temp
          int temp = array[i];
          array[i] = array[j];
          array[j] = temp;
        }
      }
    }
    System.out.println(Arrays.toString(array));
  }
}
import java.util.Arrays;
import java.util.Scanner;

// 二分查找 折半查找法  从中间斩断,比较值。继续比较
public class Test11 {

  public static void main(String[] args) {
    // 二分查找法 插入排序
    int[] array = { 3, 10, 15, 22, 33, 51, 77, 88 };
    System.out.println(Arrays.toString(array));
    Scanner input = new Scanner(System.in);
    do {

      System.out.print("输入需要插入的数据:");
      int number = input.nextInt();
       // 每次获取最左边的数和最右边的数 
      int left = 0;
      int right = array.length - 1;
      int result = recursion(array, left, right, number);
      System.out.println(result);
      int[] newArray = new int[array.length + 1];
      for (int i = 0; i < newArray.length; i++) {
        if (i < result) {
          newArray[i] = array[i];
        } else if (i == result) {
          newArray[i] = number;
        } else {
          newArray[i] = array[i - 1];
        }
      }
      array = newArray;
      System.out.println(Arrays.toString(array));
    } while (true);
  }

    //递归
  public static int recursion(int[] array, int left, int right, int number) {
    // 如果大于右边,或者小于左边
    if (array[0] > number)
      return 0;
    else if (array[array.length - 1] < number)
      return array.length;
      
    int center = (left + right) / 2;
    if (left == right - 1)
      return right;
    if (array[center] > number) {
      return recursion(array, left, center, number);
    } else {
      return recursion(array, center, right, number);
    }
  }

}
//for循环打印矩形
public class Rect {

  public void show(int width, int height) {

    for (int i = 0; i < width; i++) {
      for (int j = 0; j < height; j++) {
        if (i == 0 || j == 0 || i == width - 1 || j == height - 1)
          System.out.print("*");
        else
          System.out.print(" ");
      }
      System.out.println();
    }
  }
}
//for循环打印菱形
public class Rhombus {

  public void show(int height) {
    int half = height / 2;
    for (int i = 1; i <= half; i++) {
      // 先打空格
      for (int j = half - i + 1; j > 0; j--) {
        System.out.print(" ");
      }
      for (int j = 0; j < 2 * i - 1; j++) {
        System.out.print("*");
      }
      System.out.println();
    }

    for (int i = 0; i < 2 * half + 1; i++) {
      System.out.print("*");
    }
    System.out.println();

    for (int i = 1; i <= half; i++) {
      // 先打空格
      for (int j = i; j > 0; j--) {
        System.out.print(" ");
      }
      for (int j = 0; j < 2 * (half - i) + 1; j++) {
        System.out.print("*");
      }
      System.out.println();
    }
  }

}
//for循环打印等腰三角形
public class Isosceles {

  public void show(int height) {
    for (int i = 1; i <= height; i++) {
      // 先打空格
      for (int j = height - i; j > 0; j--) {
        System.out.print(" ");
      }
      for (int j = 0; j < 2 * i - 1; j++) {
        System.out.print("*");
      }
      System.out.println();
    }
  }
}
//for循环打印之间三角形
public class Triangle {

  public void show(String str, int height) {
    for (int i = 0; i < height; i++) {
      for (int j = 0; j < i + 1; j++) {
        System.out.print(str);
      }
      System.out.println();
    }
  }

}