[DataStructures] 스택(Stack) - 동적스택(dynamicStack)

 스택(Stack) - 동적스택(dynamicStack)

- 스택 오버플로우(stack overflow)날 경우 스택 사이즈를 동적으로 늘린다

1. 구현

1) 변수 초기화

private int top; private int[] stackArray; private int stackSize; public DynamicStack(int size){ this.top = -1; this.stackSize = size; this.stackArray = new int[stackSize]; }

2) push() and isStackFull()

public void push(int element)throws Exception{ if(this.isStackFull()){ System.out.println("Stack is full, We increase a stack size"); this.increaseCapacity(); } System.out.println("adding:"+element); this.stackArray[++top] = element; } public boolean isStackFull(){ return (stackSize-1 == top); }  

3) increaseCapacity()

public void increaseCapacity(){ int[] newArray = new int[stackSize *2]; for(int i = 0; i<stackArray.length;i++){ newArray[i] = this.stackArray[i]; } this.stackArray = newArray; this.stackSize = this.stackSize *2; }  

- 새로운 배열을 만들어 기존의 값을 넣는다

- 기존 배열을 새로운 배열로 변경한다

4) pop() and isStackEmpty()

public int pop()throws Exception{ if(this.isStackEmpty()){ throw new Exception("Stack is empty"); } int entity = stackArray[top--]; System.out.println("poping:"+entity); return entity; } public boolean isStackEmpty(){ return ( top == -1); }  

5) peek()

public int peek(){ System.out.println("peek:"+stackArray[top]); return stackArray[top]; }  

6) main()

public static void main(String[]args){ DynamicStack s1 = new DynamicStack(3); try{ s1.push(1); s1.push(2); s1.push(3); s1.push(4); s1.push(5); s1.pop(); s1.peek(); s1.pop(); s1.push(6); s1.push(7); s1.push(8); s1.push(9); }catch(Exception e){ System.out.println(e.getMessage()); } }