Finished assignment

IntListReview.iml

@@ -7,5 +7,37 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit5.8.1">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-api-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/opentest4j-1.2.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-platform-commons-1.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/apiguardian-api-1.1.2.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-params-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-engine-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-platform-engine-1.8.1.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library>
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-api-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/opentest4j-1.2.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-platform-commons-1.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/apiguardian-api-1.1.2.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-params-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-jupiter-engine-5.8.1.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/junit-platform-engine-1.8.1.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>

src/ArrayIntList.java

@@ -0,0 +1,337 @@
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+public class ArrayIntList implements IntList{
+    //internal (private) representation
+    private int[] buffer;
+    private int size;              // number of "spots used" in the int buffer
+    private final int INITIAL_CAPACITY = 10;
+    public ArrayIntList() {
+        buffer = new int[INITIAL_CAPACITY];
+        size = 0;
+    }
+
+    /**
+     * Prepends (inserts) the specified value at the front of the list (at index 0).
+     * Shifts the value currently at the front of the list (if any) and any
+     * subsequent values to the right.
+     * <p>
+     * Slow, linear time O(size) - shifts size items right
+     *
+     * @param value value to be inserted
+     */
+    @Override
+    public void addFront(int value) {
+        // check if full
+        if (size == buffer.length) {
+            resize(2*buffer.length);
+        }
+
+        // open a spot at index 0 where value will be saved
+        // shift everything over to the right by 1 position
+        for (int i = size; i >= 1; i--) {
+            buffer[i] = buffer[i-1];
+        }
+
+        //put value in position[0]
+        buffer[0] = value;
+        size++;
+    }
+
+    // slow method, linear time O(n)
+    private void resize(int newSize) {
+        // create a new array that is of the new size
+        int[] temp = new int[newSize];
+
+        // copy over values from the existing buffer
+        for (int i = 0; i < size; i++) {
+            temp[i] = buffer[i];
+        }
+
+        // make the switchover
+        buffer = temp;
+    }
+
+    /**
+     * Appends (inserts) the specified value at the back of the list (at index size()-1).
+     * <p>
+     * Fast, constant time if no resize, O(1)
+     * can be slow if resize is needed
+     *
+     * @param value value to be inserted
+     */
+    @Override
+    public void addBack(int value) {
+        if (size == buffer.length) {
+            // if the size matches the capacity, then I know I'm "full"
+            // and I need to resize (create a new larger buffer and copy
+            // the values over from the older smaller buffer)
+
+            // make the resize twice the existing capacity
+            resize(2*buffer.length);
+        }
+
+        buffer[size] = value;
+        size++;
+    }
+
+    /**
+     * Inserts the specified value at the specified position in this list.
+     * Shifts the value currently at that position (if any) and any subsequent
+     * values to the right.
+     * <p>
+     * worst case add at index and resize - O(n) - linear <p>
+     * best case add at index size  - - - - O(1) - constant <p>
+     * average case - - - - - - - - - - - - O(1/2n)
+     *
+     * @param index index at which the specified value is to be inserted
+     * @param value value to be inserted
+     * @throws IndexOutOfBoundsException if the index is out of range
+     */
+    @Override
+    public void add(int index, int value) {
+        // check if index is out of range
+        if (index < 0 || index > size) {
+            throw new IndexOutOfBoundsException("Index out of range!");
+        }
+        // adding last item?
+        else if (size == index){
+            addBack(value);
+
+        }
+        else {
+            // shifts all items over to right (if needed)
+            for (int i = size; i > index; i--) {
+                // resize
+                if (size == buffer.length) {
+                    resize(2*buffer.length);
+                }
+                buffer[i] = buffer[i-1];
+            }
+            buffer[index] = value;
+        }
+        size++;
+    }
+
+    /**
+     * Removes the value located at the front of the list
+     * (at index 0), if it is present.
+     * <p>
+     * Shifts any subsequent values to the left.
+     * slow, constant time, O(size)/O(n)
+     */
+    @Override
+    public void removeFront() {
+        // shift everything to the left by 1
+        for (int i = 0; i < size; i++) {
+            // if the size is as large as buffer length, do something special
+            if(i == (buffer.length-1)  && size == buffer.length) {
+                buffer[i] = 0;
+            } else {
+                buffer[i] = buffer[i + 1];
+            }
+        }
+
+        // lower size
+        size--;
+    }
+
+    /**
+     * Removes the value located at the back of the list
+     * (at index size()-1), if it is present.
+     * <p>
+     * fast, constant time, O(1)
+     */
+    @Override
+    public void removeBack() {
+        if(size==0) {
+            throw new IllegalStateException("ArrayList is empty!");
+        }
+        buffer[--size] = 0;
+    }
+
+    /**
+     * Removes the value at the specified position in this list.
+     * Shifts any subsequent values to the left. Returns the value
+     * that was removed from the list.
+     * <p>
+     * worst case remove at index 0 and resize - O(n) - linear <p>
+     * best case remove at index size  - - - - - O(1) - constant <p>
+     * average case  - - - - - - - - - - - - - - O(1/2n)
+     *
+     * @param index the index of the value to be removed
+     * @return the value previously at the specified position
+     * @throws IndexOutOfBoundsException if the index is out of range
+     */
+    @Override
+    public int remove(int index) {
+        if(size==0) {
+            throw new IllegalStateException("ArrayList is empty!");
+        } else if (index < 0 || index > size-1) {
+            throw new IndexOutOfBoundsException("Out of index range!");
+        }
+
+        int savedValue = buffer[index];
+        // shifts all other units to the left
+        for (int i = index; i < size; i++) {
+            // if the size is as large as buffer length, do something special
+            if(i == (buffer.length-1)  && size == buffer.length) {
+                buffer[i] = 0;
+            } else {
+                buffer[i] = buffer[i + 1];
+            }
+        }
+        size--;
+        return savedValue;
+    }
+
+    /**
+     * Returns the value at the specified position in the list.
+     * This method is fast, constant time or also known as, O(1).
+     *
+     * @param index index of the value to return
+     * @return the value at the specified position in this list
+     * @throws IndexOutOfBoundsException if the index is out of range
+     */
+    @Override
+    public int get(int index) {
+        if (index < 0 || index > size-1 || size == 0) {
+            throw new IndexOutOfBoundsException("Out of index range!");
+        }
+        return buffer[index];
+    }
+
+    /**
+     * Returns true if this list contains the specified value.
+     * <p>
+     * W.C. when return false or at end of list - linear time O(n)
+     *
+     * @param value value whose presence in this list is to be searched for
+     * @return true if this list contains the specified value
+     */
+    @Override
+    public boolean contains(int value) {
+        for (int i = 0; i < size; i++) {
+            if(buffer[i] == value) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the index of the first occurrence of the specified value
+     * in this list, or -1 if this list does not contain the value.
+     * <p>
+     * Fast, constant time, O(1)
+     *
+     * @param value value to search for
+     * @return the index of the first occurrence of the specified value in this list
+     * or -1 if this list does not contain the value
+     */
+    @Override
+    public int indexOf(int value) {
+        for (int i = 0; i < size; i++) {
+            if(buffer[i] == value) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    /**
+     * Returns true if this list contains no values.
+     * <p>
+     * Fast, constant time, O(1)
+     *
+     * @return true if this list contains no values
+     */
+    @Override
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    /**
+     * Returns the number of values in this list.
+     * <p>
+     * This is a fast method, constant time, O(1)
+     *
+     * @return the number of values in this list
+     */
+    @Override
+    public int size() {
+        return size;
+    }
+
+    /**
+     * Removes all the values from this list.
+     * The list will be empty after this call returns.
+     * Fast method, constant time, O(1)
+     */
+    @Override
+    public void clear() {
+        buffer = new int[INITIAL_CAPACITY];
+        size = 0;
+    }
+
+    /**
+     * Returns an iterator over elements of type {@code T}.
+     *
+     * @return an Iterator.
+     */
+    @Override
+    public Iterator<Integer> iterator() {
+        return new ArrayIntListIterator();
+    }
+
+    /**
+     * Transfers the array into a string value
+     * <p>
+     * O(n) linear time b/c visits every item
+     *
+     * @return string
+     */
+    @Override
+    public String toString() {
+        if (size == 0) {
+            return "[]";
+        }
+
+        StringBuilder sb = new StringBuilder();
+        sb.append("[");
+
+        for (int i = 0; i < size; i++) {
+            sb.append(buffer[i]);
+            sb.append(i == size-1 ? "" : ", ");
+        }
+
+        sb.append("]");
+        return sb.toString();
+    }
+
+    // nested or inner class (helper class)
+    public class ArrayIntListIterator implements Iterator<Integer>{
+        private int currenPosition;
+        public ArrayIntListIterator() {
+            currenPosition = 0;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return currenPosition < size();
+        }
+
+        @Override
+        public Integer next() {
+            //just to be safe - make sure there is a next
+            if (!hasNext()) {
+                throw new NoSuchElementException();
+            }
+
+            int value = get(currenPosition);
+            currenPosition++;
+            return value;
+        }
+    }
+
+} // end of ArrayIntList