how to add random number to an array
Question by Lish
This is classwork. I’ve been reading and searching and everything is telling me to use the java.util.Random of which I understand how that works and wish I could use it. but my assignment specifically tells me to use the (int) (Math.random * number) of which I am having difficulty seeing where to apply into my array. everything I’ve seen has been the Random pulled from java.
It is the generate 100 random integers 0-9 and how many times they occur. If someone can assist?
My error is – Exception in “main” java.lang.array index out of bounds exemption:10 and obviously there is something in my code wrong too.
public class NumberOfTimes{
public static void main(String[] args){
int rand = (int)(Math.random() * 10);
int[] counts = new int [10];
for(int i = 0; i < 100; i++){
counts[i]++;
}//end for
System.out.println("numbert" + "occurence ");
for (int num = 0; num < counts.length; num++){
System.out.println(num + "t" + counts[num]);
}//end for
}//end main
}//end NumberOfTimes
Answer by Evgeniy Dorofeev
make this change
int[] counts = new int[100];
for (int i = 0; i < 100; i++) {
counts[i] = (int) (Math.random() * 10);
}// end for
Answer by Starx
Your array can only hold 10 items, and on your loop you are accessing more than 10. Can be solved in two ways.
-
Either Increase your array length
int[] counts = new int [100]; -
Or either decrease your count in for loop.
for(int i = 0; i < 10; i++){
