array

Question

public class MyClass {
public static void main(String args[]) {
int []n ={1,2,5,1,2,3,4,2,4,1};
int [] occ = new int[6];

for(int i = 0; i <n.length; i++)
++ occ [n[i]];

System.out.println(occ[1]);
System.out.println(occ[4]);
}
};

// still dont know why it gives such a result ; I mean 3 and 2

Answer 1

Java initializes occ contents to 0. The rest is about handtracing.

++occ[n[0]]
++occ[1]
occ[1] is now 1.

++occ[n[1]]
++occ[2]
occ[2] is now 1

... (I'll leave the rest to you)

An easy way would be to inspect the contents of n. We can see that 1 occurs 3 times in n, and we know that the contents of n will be iterated through and used as the index for occ. So, occ[1] would be 3.

In the end, occ[1] and occ[4] is 3 and 2 respectively

Answer 2

|So its like an Histogram ; captures the amount of ocurrences??; this is more complex than I thought.