Question

Ok I am relatively new to Java Programming, but have previous experience in C++. I want to search an array for a specific item, but what if there are more than one of the same specific item? Would it be best to use a temporary array to store all found items in the array and return the temporary array?

Note: I’m trying to find the best way of doing this with memory management and speed. And it’s not for Home work:)

Answer 1

I would use a “ready to use” implementation like a HashMap. You say “search”, so I believe that you have a searchkey (in my proposal the String) under wich you can store your data (for example an Integer).

Map<String, List<Integer>>  map = new HashMap<String, List<Integer>>(); 

    void storeValue(final String key, final Integer value) {
        List<Integer> l = this.map.get(key);
        if (l == null) {
            synchronized (this.map) {
                if (l == null) {
                    l = new Vector<Integer>();
                    this.map.put(key, l);
                }
            }
        }
        l.add(value);
    }

    List<Integer> searchByKey(final String key) {
        return this.map.get(key);
    }

With this, you can store multiple Integers @ one key. Of course you can store other Object than the Integers.