From f894b40fe668c03065e6a63e405a5675d4bb12c7 Mon Sep 17 00:00:00 2001 From: Dhananjay Singh Date: Mon, 11 Feb 2019 09:00:35 +0530 Subject: [PATCH] Char stack (#6248) * Corrected Package name * Char stack * Changed file names --- .../com/baeldung/charstack/CharStack.java | 37 +++++++++++ .../charstack/CharStackWithArray.java | 48 ++++++++++++++ .../charstack/EmptyStackException.java | 9 +++ .../queueInterface/CustomBaeldungQueue.java | 2 +- .../baeldung/charstack/CharStackUnitTest.java | 50 ++++++++++++++ .../charstack/CharStackUsingJavaUnitTest.java | 53 +++++++++++++++ .../charstack/CharStackWithArrayUnitTest.java | 65 +++++++++++++++++++ .../CustomBaeldungQueueUnitTest.java | 2 +- .../queueinterface/PriorityQueueUnitTest.java | 2 +- 9 files changed, 265 insertions(+), 3 deletions(-) create mode 100644 core-java-collections/src/main/java/com/baeldung/charstack/CharStack.java create mode 100644 core-java-collections/src/main/java/com/baeldung/charstack/CharStackWithArray.java create mode 100644 core-java-collections/src/main/java/com/baeldung/charstack/EmptyStackException.java create mode 100644 core-java-collections/src/test/java/com/baeldung/charstack/CharStackUnitTest.java create mode 100644 core-java-collections/src/test/java/com/baeldung/charstack/CharStackUsingJavaUnitTest.java create mode 100644 core-java-collections/src/test/java/com/baeldung/charstack/CharStackWithArrayUnitTest.java diff --git a/core-java-collections/src/main/java/com/baeldung/charstack/CharStack.java b/core-java-collections/src/main/java/com/baeldung/charstack/CharStack.java new file mode 100644 index 0000000000..f789a68d90 --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/charstack/CharStack.java @@ -0,0 +1,37 @@ +package com.baeldung.charstack; + +import java.util.Iterator; +import java.util.LinkedList; + +public class CharStack { + + private LinkedList items; + + public CharStack() { + this.items = new LinkedList(); + } + + public void push(Character item) { + items.push(item); + } + + public Character peek() { + return items.getFirst(); + } + + public Character pop() { + + Iterator iter = items.iterator(); + Character item = iter.next(); + if (item != null) { + iter.remove(); + return item; + } + return null; + } + + public int size() { + return items.size(); + } + +} diff --git a/core-java-collections/src/main/java/com/baeldung/charstack/CharStackWithArray.java b/core-java-collections/src/main/java/com/baeldung/charstack/CharStackWithArray.java new file mode 100644 index 0000000000..ed7fa3f253 --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/charstack/CharStackWithArray.java @@ -0,0 +1,48 @@ +package com.baeldung.charstack; + +public class CharStackWithArray { + + private char[] elements; + private int size; + + public CharStackWithArray() { + size = 0; + elements = new char[4]; + } + + public int size() { + return size; + } + + public char peek() { + if (size == 0) { + throw new EmptyStackException(); + } + return elements[size - 1]; + } + + public char pop() { + if (size == 0) { + throw new EmptyStackException(); + } + + return elements[--size]; + } + + public void push(char item) { + ensureCapacity(size + 1); + elements[size] = item; + size++; + } + + private void ensureCapacity(int newSize) { + char newBiggerArray[]; + + if (elements.length < newSize) { + newBiggerArray = new char[elements.length * 2]; + System.arraycopy(elements, 0, newBiggerArray, 0, size); + elements = newBiggerArray; + } + } + +} diff --git a/core-java-collections/src/main/java/com/baeldung/charstack/EmptyStackException.java b/core-java-collections/src/main/java/com/baeldung/charstack/EmptyStackException.java new file mode 100644 index 0000000000..f005854e7f --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/charstack/EmptyStackException.java @@ -0,0 +1,9 @@ +package com.baeldung.charstack; + +public class EmptyStackException extends RuntimeException { + + public EmptyStackException() { + super("Stack is empty"); + } + +} diff --git a/core-java-collections/src/main/java/com/baeldung/queueInterface/CustomBaeldungQueue.java b/core-java-collections/src/main/java/com/baeldung/queueInterface/CustomBaeldungQueue.java index 6b088a5079..4fcc211812 100644 --- a/core-java-collections/src/main/java/com/baeldung/queueInterface/CustomBaeldungQueue.java +++ b/core-java-collections/src/main/java/com/baeldung/queueInterface/CustomBaeldungQueue.java @@ -1,4 +1,4 @@ -package com.baeldung.queueinterface; +package com.baeldung.queueInterface; import java.util.AbstractQueue; import java.util.Iterator; diff --git a/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUnitTest.java b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUnitTest.java new file mode 100644 index 0000000000..a20526fd9d --- /dev/null +++ b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUnitTest.java @@ -0,0 +1,50 @@ +package com.baeldung.charstack; + +import static org.junit.Assert.assertEquals; + +import org.junit.jupiter.api.Test; + +public class CharStackUnitTest { + + @Test + public void whenCharStackIsCreated_thenItHasSize0() { + + CharStack charStack = new CharStack(); + + assertEquals(0, charStack.size()); + } + + @Test + public void givenEmptyCharStack_whenElementIsPushed_thenStackSizeisIncreased() { + + CharStack charStack = new CharStack(); + + charStack.push('A'); + + assertEquals(1, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPoppedFromStack_thenElementIsRemovedAndSizeChanges() { + + CharStack charStack = new CharStack(); + charStack.push('A'); + + char element = charStack.pop(); + + assertEquals('A', element); + assertEquals(0, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPeeked_thenElementIsNotRemovedAndSizeDoesNotChange() { + CharStack charStack = new CharStack(); + charStack.push('A'); + + char element = charStack.peek(); + + assertEquals('A', element); + assertEquals(1, charStack.size()); + } + +} diff --git a/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUsingJavaUnitTest.java b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUsingJavaUnitTest.java new file mode 100644 index 0000000000..964b901ae0 --- /dev/null +++ b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackUsingJavaUnitTest.java @@ -0,0 +1,53 @@ +package com.baeldung.charstack; + +import static org.junit.Assert.assertEquals; + +import java.util.Stack; + +import org.junit.jupiter.api.Test; + +public class CharStackUsingJavaUnitTest { + + @Test + public void whenCharStackIsCreated_thenItHasSize0() { + + Stack charStack = new Stack<>(); + + assertEquals(0, charStack.size()); + } + + @Test + public void givenEmptyCharStack_whenElementIsPushed_thenStackSizeisIncreased() { + + Stack charStack = new Stack<>(); + + charStack.push('A'); + + assertEquals(1, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPoppedFromStack_thenElementIsRemovedAndSizeChanges() { + + Stack charStack = new Stack<>(); + charStack.push('A'); + + char element = charStack.pop(); + + assertEquals('A', element); + assertEquals(0, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPeeked_thenElementIsNotRemovedAndSizeDoesNotChange() { + + Stack charStack = new Stack<>(); + charStack.push('A'); + + char element = charStack.peek(); + + assertEquals('A', element); + assertEquals(1, charStack.size()); + } + +} diff --git a/core-java-collections/src/test/java/com/baeldung/charstack/CharStackWithArrayUnitTest.java b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackWithArrayUnitTest.java new file mode 100644 index 0000000000..df90b8f0a4 --- /dev/null +++ b/core-java-collections/src/test/java/com/baeldung/charstack/CharStackWithArrayUnitTest.java @@ -0,0 +1,65 @@ +package com.baeldung.charstack; + +import static org.junit.Assert.assertEquals; + +import org.junit.jupiter.api.Test; + +public class CharStackWithArrayUnitTest { + + @Test + public void whenCharStackIsCreated_thenItHasSize0() { + + CharStackWithArray charStack = new CharStackWithArray(); + + assertEquals(0, charStack.size()); + } + + @Test + public void givenEmptyCharStack_whenElementIsPushed_thenStackSizeisIncreased() { + + CharStackWithArray charStack = new CharStackWithArray(); + + charStack.push('A'); + + assertEquals(1, charStack.size()); + } + + @Test + public void givenEmptyCharStack_when5ElementIsPushed_thenStackSizeis() { + + CharStackWithArray charStack = new CharStackWithArray(); + + charStack.push('A'); + charStack.push('B'); + charStack.push('C'); + charStack.push('D'); + charStack.push('E'); + + assertEquals(5, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPoppedFromStack_thenElementIsRemovedAndSizeChanges() { + + CharStackWithArray charStack = new CharStackWithArray(); + charStack.push('A'); + + char element = charStack.pop(); + + assertEquals('A', element); + assertEquals(0, charStack.size()); + } + + @Test + public void givenCharStack_whenElementIsPeeked_thenElementIsNotRemovedAndSizeDoesNotChange() { + + CharStackWithArray charStack = new CharStackWithArray(); + charStack.push('A'); + + char element = charStack.peek(); + + assertEquals('A', element); + assertEquals(1, charStack.size()); + } + +} diff --git a/core-java-collections/src/test/java/com/baeldung/queueinterface/CustomBaeldungQueueUnitTest.java b/core-java-collections/src/test/java/com/baeldung/queueinterface/CustomBaeldungQueueUnitTest.java index 6dec768542..7471d9841d 100644 --- a/core-java-collections/src/test/java/com/baeldung/queueinterface/CustomBaeldungQueueUnitTest.java +++ b/core-java-collections/src/test/java/com/baeldung/queueinterface/CustomBaeldungQueueUnitTest.java @@ -1,4 +1,4 @@ -package com.baeldung.queueinterface; +package com.baeldung.queueInterface; import org.junit.Before; import org.junit.Test; diff --git a/core-java-collections/src/test/java/com/baeldung/queueinterface/PriorityQueueUnitTest.java b/core-java-collections/src/test/java/com/baeldung/queueinterface/PriorityQueueUnitTest.java index c5b564b55b..748099e8d1 100644 --- a/core-java-collections/src/test/java/com/baeldung/queueinterface/PriorityQueueUnitTest.java +++ b/core-java-collections/src/test/java/com/baeldung/queueinterface/PriorityQueueUnitTest.java @@ -1,4 +1,4 @@ -package com.baeldung.queueinterface; +package com.baeldung.queueInterface; import org.junit.Before; import org.junit.Test;