一维数组的应用

1.求一组数的最大值

思路:从这组数中选取一个值，然后让它依次和其他的数进行大小比较.

public class Demo1 {
    public static void main(String[] args) {
        int[] sums = new int[]{1,5,777,43,5,577,666,778};
        int max = sums[0];
        for (int i = 0; i < sums.length; i++) {
            if(max<sums[i]){
                max=sums[i];
            }

        }
        System.out.println(max);
    }
}

2.在一组数中插入一个数

思路:先定义一个新数组,将原数组的值对应赋给新数组.然后确定插入的位置,从后往前,依次将前一个数的值赋给后一个数.

import java.util.Scanner;
public class Demo2 {
    public static void main(String[] args) {
        int[] a ={90,87,65,43,21};
        int[] b =new int[a.length+1];
        for (int i = 0; i <b.length-1 ; i++) {
            b[i]=a[i];
        }
        System.out.println("插入一个数");
        Scanner sc = new Scanner(System.in);
        int c = sc.nextInt();

        int index=b.length-1;
        for (int i = 0; i <b.length; i++) {
            if(c>b[i]){
                index=i;
                break;
            }


        }
        for (int i = b.length-1; i>index  ; i--) {
            b[i]=b[i-1];

        }
        b[index]=c;
        for (int i = 0; i < b.length; i++) {
            System.out.println(b[i]);

        }
    }
}

 

 3.冒泡排序-----数字升序排序

思路:两两相比小靠前,找到比较轮数与比较次数的关系.

//使用冒泡排序对输入的5名学员成绩进行升序排列
import java.util.Scanner;
public class Demo6 {
    public static void main(String[] args) {
        int[] student=new int[5];
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入5名学生成绩");
        for (int i = 0; i < student.length; i++) {
            student[i]=sc.nextInt();
        }
        for (int i = 0; i < student.length-1; i++) {
            for (int j =0 ; j <student.length-1-i ; j++) {
                if(student[j]>student[j+1]){
                    int index=student[j];
                    student[j]=student[j+1];
                    student[j+1]=index;
                }


            }

        }
        for (int k = 0; k < student.length; k++) {
            System.out.println(student[k]);

        }

    }
}