Java/Java入门 - 数组进阶.txt

1.数组的复制
package step1;
 
import java.util.Scanner;
 
public class HelloWorld {
	public static void main(String[] args) {
		//动态构建arr1
		int[] arr1 = new int[3];
		Scanner sc = new Scanner(System.in);
		for(int i = 0 ; i< arr1.length ; i++){
			arr1[i] = sc.nextInt();
		}
		/********** Begin **********/
		//创建数组arr2
        int[] arr2 = new int[arr1.length];
 
        //使用for循环将arr1的数据复制给arr2
 
        for (int j = 0; j < arr1.length; j++) {
            arr2[j] = arr1[j];
        }
 
        //输出arr2
        for (int array : arr2)
            System.out.println(array);
		/********** End **********/
	}
}
2.数组中元素的查找
package step2;
 
import java.util.Scanner;
 
public class HelloWorld {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		//str为要查找的字符串
		String str = sc.next();
		
		/********** Begin **********/
		//创建数组   arr  给数组赋值 {"张三","张三丰","张无忌","王二麻子","张富贵"}
		String[] arr = {"张三", "张三丰", "张无忌", "王二麻子", "张富贵"};
 
        for (int i = 0; i < arr.length; i++) {
            int j = i + 1;
            if (str.equals(arr[i]))
                System.out.println(str + "在数组的第" + j + "个位置");
        }
		
		/********** End **********/
	}
}
3.交换算法
package step3;
 
import java.util.Scanner;
 
public class HelloWorld {
 
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		/********** Begin **********/
		//将a的值赋给b   b的值赋给a
		
		int temp=a;
        a=b;
        b=temp;
 
		/********** End **********/
		System.out.println(a);
		System.out.println(b);
	}
	
}
4.选择排序
package step4;
 
import java.util.Arrays;
import java.util.Scanner;
 
public class HelloWorld {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//动态创建数组
		int[] arr = new int[sc.nextInt()];
		for(int i = 0 ; i< arr.length ; i++){
			arr[i] = sc.nextInt();
		}
		/********** Begin **********/
		for (int i = 0; i < arr.length - 1; i++) {
            int k = i;
            for (int j = k + 1; j < arr.length; j++) {
                if (arr[j] > arr[k]) {
                    k = j;
                }
            }
            if (i != k) {
                int temp = arr[i];
                arr[i] = arr[k];
                arr[k] = temp;
            }
        }
        System.out.println(Arrays.toString(arr));	
		
		/********** End **********/
	}
}
5.冒泡排序
package step5;
 
import java.util.Arrays;
import java.util.Scanner;
 
public class HelloWorld {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//动态创建数组
		int[] arr = new int[sc.nextInt()];
		for(int i = 0 ; i< arr.length ; i++){
			arr[i] = sc.nextInt();
		}
		/********** Begin **********/
	    for (int i = 0; i < arr.length - 1; i++) {
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j] > arr[j + 1]) {
                    int temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
        System.out.println(Arrays.toString(arr));
		
		/********** End **********/
	}
}