import java.util.Random;public class Test { public static void main(String[] args) throws Exception { int[] ints = new int[5]; Random random = new Random(); for (int i = 0; i < ints.length; i++) { ints[i] = random.nextInt(20); } for (int i = 0; i < ints.length; i++) { System.out.println(ints[i]); } } }
public static void main(String[] args) throws Exception {
int[] ints = new int[5];
Random random = new Random();
for (int i = 0; i < ints.length; i++) {
ints[i] = random.nextInt(20);
}
for (int i = 0; i < ints.length; i++) {
System.out.println(ints[i]);
}
}
}
{
System.out.print((int)(Math.random()*20+1));
}
random.nextInt(20)这个方位是[0,20)
不是从1,2,20中取到20,而且还多取了一个0
Math.random()的范围是[0,1)
Math.random()*20+1的范围是[1,21)
所以取值范围是[1,20]
~~~~
该如何写?
super();}public static void main(String[] args) throws Exception { int[] nus = new int[5];
int nu=0;
int m=0;
boolean t; Random random = new Random();
nus[0]=(int) (Math.random() * 20 + 1);
for(int i=1;i<nus.length;i++)
{
nu=(int) (Math.random() * 20+ 1);
m=0; for(int a=0;a<i;a++)
{
if(nu==nus[a])
{
i--;
m=1;
continue;
}
}
if(m==0){
nus[i]=nu;
}
}
for (int i = 0; i < nus.length; i++) {
System.out.println(nus[i]);
} }}
import java.util.Random;
和Random random = new Random();
可以不要
没注意,呵呵