I have to write a program that generate random integers from 0 to 9 for 1000 times and count repeated numbers. So output should be like:
0 used 123 times, 1 used 89 times, 2 301 times, . . 9 used 23 times
I must use math.random for this. I can generate numbers but how can I use array and loop for this?
Thanks.
If you can use java.util.Random, you don't need array and loop.
Try this.
System.out.println(new Random().ints(1000, 0, 10)
.boxed()
.collect(Collectors.groupingBy(i -> i, Collectors.counting()))
.entrySet().stream()
.map(e -> String.format("%d used %d times", e.getKey(), e.getValue()))
.collect(Collectors.joining(", ")));
result
0 used 109 times, 1 used 97 times, 2 used 81 times, 3 used 107 times, 4 used 121 times, 5 used 100 times, 6 used 97 times, 7 used 96 times, 8 used 80 times, 9 used 112 times
Try this code you will get your desired output:
**import** java.util.HashMap;
**import** java.util.Map;
public **class** RandomCounting
{
static **Map**<Integer,Integer> result=new **HashMap**<Integer,Integer>();
static int[] a=new int[10];
public static void main(String[] args)
{
for (int i = 0; i < 1000; i++)
{
int value=(int)(Math.random()*10);
//System.out.print(value+" ");
switch(value)
{
case 0:result.put(0,a[0]++);break;
case 1:result.put(1,a[1]++);break;
case 2:result.put(2,a[2]++);break;
case 3:result.put(3,a[3]++);break;
case 4:result.put(4,a[4]++);break;
case 5:result.put(5,a[5]++);break;
case 6:result.put(6,a[6]++);break;
case 7:result.put(7,a[7]++);break;
case 8:result.put(8,a[8]++);break;
case 9:result.put(9,a[9]++);break;
}
//System.out.print(value+" ");
}
for (int i = 0; i < 10; i++)
{
System.out.println(i+" used "+result.get(i)+" times");
}
}
}
