用java.随机输入3个数a,b,c，按大小顺序输出。

import java.util.Arrays;
import java.util.Random;

public class Test {

public static void main(String args[]) {
Random r = new Random();
int[] arr=new int[3];
for (int i = 0; i < 3; i++) {
arr[i]=r.nextInt(50);//如果这几个数不要指定 在几范围内，可写成arr[i]=r.nextInt();这里就在0-50间的数
System.out.println("第"+(i+1)+"个数是"+arr[i]);
}
Arrays.sort(arr);
for (int i = 0; i < arr.length; i++) {
System.out.println(arr[i]);
}
}

}

int a= System.in.read();
int b= System.in.read();
int c= System.in.read();
int d=0;
if(a>=b&&a>=c){
System.out.println(a);
if(b>=c){
System.out.println(b);
}else{
System.out.println(c);
}
}else if(b>=a&&b>=c){
System.out.println(a);
if(a>=c){
System.out.println(a);
}else{
System.out.println(c);
}
}else if(c>=b&&c>=a){
System.out.println(a);
if(a>=b){
System.out.println(a);
}else{
System.out.println(b);
}
}

public
class
Test
{
public
static
void
main(String[]
args)
{
System.out.print("请输入三个数，用空格分开：");
Scanner
sc
=
new
Scanner(System.in);
int[]
a
=
new
int[3];
for
(int
i
=
0;
i
<
3;
i++)
{
a[i]
=
sc.nextInt();
}
int
temp
=
0;
if
(a[0]
<
a[1])
{
temp
=
a[0];
a[0]
=
a[1];
a[1]
=
temp;
}
if
(a[1]
<
a[2])
{
temp
=
a[1];
a[1]
=
a[2];
a[2]
=
temp;
}
if
(a[0]
<
a[1])
{
temp
=
a[0];
a[0]
=
a[1];
a[1]
=
temp;
}
System.out.println("从大到小为："
+
a[0]
+
"
"
+
a[1]
+
"
"
+
a[2]);
}
}

将3个数存入数组

用Arrays.sort(数组) 这个类的方法来排序