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Format code in StackArray

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This commit is contained in:
Libin Yang
2019-01-06 08:56:51 +08:00
committed by GitHub
parent 29b7ad43d1
commit fc64d05b5c
1 changed files with 128 additions and 122 deletions
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250
DataStructures/Stacks/StackArray.java
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@ -1,6 +1,6 @@
/** /**
* This class implements a Stack using a regular array. * This class implements a Stack using a regular array.
* * <p>
* A stack is exactly what it sounds like. An element gets added to the top of * A stack is exactly what it sounds like. An element gets added to the top of
* the stack and only the element on the top may be removed. This is an example * the stack and only the element on the top may be removed. This is an example
* of an array implementation of a Stack. So an element can only be added/removed * of an array implementation of a Stack. So an element can only be added/removed
@ -8,139 +8,145 @@
* array implementation it does. * array implementation it does.
* *
* @author Unknown * @author Unknown
*
*/ */
public class StackArray{ public class StackArray {
/** /**
* Main method * Main method
* *
* @param args Command line arguments * @param args Command line arguments
*/ */
public static void main(String[] args) { public static void main(String[] args) {
StackArray myStackArray = new StackArray(4); //Declare a stack of maximum size 4 // Declare a stack of maximum size 4
//Populate the stack StackArray myStackArray = new StackArray(4);
myStackArray.push(5);
myStackArray.push(8);
myStackArray.push(2);
myStackArray.push(9);
System.out.println("*********************Stack Array Implementation*********************"); // Populate the stack
System.out.println(myStackArray.isEmpty()); //will print false myStackArray.push(5);
System.out.println(myStackArray.isFull()); //will print true myStackArray.push(8);
System.out.println(myStackArray.peek()); //will print 9 myStackArray.push(2);
System.out.println(myStackArray.pop()); //will print 9 myStackArray.push(9);
System.out.println(myStackArray.peek()); // will print 2
}
/** The max size of the Stack */ System.out.println("*********************Stack Array Implementation*********************");
private int maxSize; System.out.println(myStackArray.isEmpty()); // will print false
System.out.println(myStackArray.isFull()); // will print true
/** The array representation of the Stack */ System.out.println(myStackArray.peek()); // will print 9
private int[] stackArray; System.out.println(myStackArray.pop()); // will print 9
System.out.println(myStackArray.peek()); // will print 2
/** The top of the stack */
private int top;
/**
* Constructor
*
* @param size Size of the Stack
*/
public StackArray(int size){
maxSize = size;
stackArray = new int[maxSize];
top = -1;
}
/**
* Adds an element to the top of the stack
*
* @param value The element added
*/
public void push(int value){
if(!isFull()){ //Checks for a full stack
top++;
stackArray[top] = value;
}else{
resize(maxSize*2);
push(value);// don't forget push after resizing
}
}
/**
* Removes the top element of the stack and returns the value you've removed
*
* @return value popped off the Stack
*/
public int pop(){
if(!isEmpty()){ //Checks for an empty stack
return stackArray[top--];
} }
if(top < maxSize/4){ /**
resize(maxSize/2); * The max size of the Stack
return pop();// don't forget pop after resizing */
private int maxSize;
/**
* The array representation of the Stack
*/
private int[] stackArray;
/**
* The top of the stack
*/
private int top;
/**
* Constructor
*
* @param size Size of the Stack
*/
public StackArray(int size) {
maxSize = size;
stackArray = new int[maxSize];
top = -1;
} }
else{
System.out.println("The stack is already empty"); /**
return -1; * Adds an element to the top of the stack
*
* @param value The element added
*/
public void push(int value) {
if (!isFull()) { // Checks for a full stack
top++;
stackArray[top] = value;
} else {
resize(maxSize * 2);
push(value); // don't forget push after resizing
}
} }
}
/** /**
* Returns the element at the top of the stack * Removes the top element of the stack and returns the value you've removed
* *
* @return element at the top of the stack * @return value popped off the Stack
*/ */
public int peek(){ public int pop() {
if(!isEmpty()){ //Checks for an empty stack if (!isEmpty()) { // Checks for an empty stack
return stackArray[top]; return stackArray[top--];
}else{ }
System.out.println("The stack is empty, cant peek");
return -1; if (top < maxSize / 4) {
resize(maxSize / 2);
return pop();// don't forget pop after resizing
} else {
System.out.println("The stack is already empty");
return -1;
}
} }
}
private void resize(int newSize){ /**
//private int[] transferArray = new int[newSize]; we can't put modifires here ! * Returns the element at the top of the stack
int[] transferArray = new int[newSize]; *
* @return element at the top of the stack
//for(int i = 0; i < stackArray.length(); i++){ the length isn't a method . */
for(int i = 0; i < stackArray.length; i++){ public int peek() {
transferArray[i] = stackArray[i]; if (!isEmpty()) { // Checks for an empty stack
stackArray = transferArray; return stackArray[top];
} else {
System.out.println("The stack is empty, cant peek");
return -1;
}
} }
maxSize = newSize;
}
/** private void resize(int newSize) {
* Returns true if the stack is empty // private int[] transferArray = new int[newSize]; we can't put modifiers here !
* int[] transferArray = new int[newSize];
* @return true if the stack is empty
*/
public boolean isEmpty(){
return(top == -1);
}
/** // for(int i = 0; i < stackArray.length(); i++){ the length isn't a method .
* Returns true if the stack is full for (int i = 0; i < stackArray.length; i++) {
* transferArray[i] = stackArray[i];
* @return true if the stack is full stackArray = transferArray;
*/ }
public boolean isFull(){ maxSize = newSize;
return(top+1 == maxSize); }
}
/** /**
* Deletes everything in the Stack * Returns true if the stack is empty
* *
* Doesn't delete elements in the array * @return true if the stack is empty
* but if you call push method after calling */
* makeEmpty it will overwrite previous public boolean isEmpty() {
* values return (top == -1);
*/ }
public void makeEmpty(){ //Doesn't delete elements in the array but if you call
top = -1; //push method after calling makeEmpty it will overwrite previous values /**
} * Returns true if the stack is full
} *
* @return true if the stack is full
*/
public boolean isFull() {
return (top + 1 == maxSize);
}
/**
* Deletes everything in the Stack
* <p>
* Doesn't delete elements in the array
* but if you call push method after calling
* makeEmpty it will overwrite previous
* values
*/
public void makeEmpty() { // Doesn't delete elements in the array but if you call
top = -1; // push method after calling makeEmpty it will overwrite previous values
}
}