4.12作业

1.定义长度位5的整型数组,输入他们的值,用冒泡排序后输出.

package a;

import java.util.*;

public class aa {

public static void main(String[] args) {
// TODO Auto-generated method stub;
int[] a = new int [5] ;
Scanner sc = new Scanner (System.in);
System.out.println("请依次输入数组各元素的值");
for (int i = 0; i < a.length; i++) {
a[i]=sc.nextInt();
}
for (int i=0;i<a.length-1;i++) {
for(int j=0;j<a.length-i-1;j++) {
if(a[j]>a[j+1]) {
int x=a[j];
a[j]=a[j+1];
a[j+1]=x;
}
}
}
for (int i = 0; i < a.length; i++) {
System.out.print(a[i] + " ");
}
}
}

2.定义数组{34,22,35,67,45,66,12,33},输入一个数a,查找在数组中是否存在,如果存在,输出下标,不存在输出"not found"

package a;

import java.util.*;

public class aa {

public static void main(String[] args) {
// TODO Auto-generated method stub;
int[] a = { 34, 22, 35, 67, 45, 66, 12, 33 };
Scanner sc = new Scanner(System.in);
System.out.println("输入数字，我将查找它是否在数组中");
int x = sc.nextInt();
int y = 0;
for (int i = 0; i < a.length; i++) {
if (x == a[i]) {
System.out.println("它的下标为：" + i);
y=1;
}
}
if (y == 0) {
System.out.println("not found");
}
}
}

3.以矩阵的形式输出一个double型二维数组（长度分别为5、4，值自己设定）的值。

package a;

import java.util.*;

public class aa {

public static void main(String[] args) {
// TODO Auto-generated method stub;
double[][] a = new double [4][5];
double x=0.1;
Scanner sc = new Scanner(System.in);
for(int i=0;i<a.length;i++) {
for(int j=0;j<a[i].length;j++) {
a[i][j]+=x;
x++;
}
}
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();
}
}
}

4.定义一个二维数组(长度分别为3,4,值自己设定),求该二维数组的最大值.

package a;

import java.util.*;

public class aa {

public static void main(String[] args) {
// TODO Auto-generated method stub;
int[][] a = new int[3][4];
int x = 1;
Scanner sc = new Scanner(System.in);
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[i].length; j++) {
a[i][j] += x;
x++;
}
}
System.out.println("输入数组为：");
int max = 0;
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[i].length; j++) {
System.out.print(a[i][j] + " ");
if (max < a[i][j]) {
max = a[i][j];
}
}
System.out.println();
}
System.out.println("输出的最大值为：" + max);
}
}