자바 스택구현

package algorithm;

 

public class IntStack {

private int max;

private int ptr;

private int[] stk;

 

public class EmptyIntStackException extends RuntimeException {

public EmptyIntStackException() {

}

}

 

public class OverflowIntStackException extends RuntimeException {

public OverflowIntStackException() {

}

}

 

public IntStack(int capacity) {

ptr = 0;

max = capacity;

try {

stk = new int[max];

} catch (OutOfMemoryError e) {

max = 0;

}

}

 

public int push(int x) throws OverflowIntStackException {

if (ptr >= max)

throw new OverflowIntStackException();

return stk[ptr++] = x;

}

 

public int pop() throws EmptyIntStackException {

if (ptr <= 0)

throw new EmptyIntStackException();

return stk[--ptr];

}

 

public int peek() throws EmptyIntStackException {

if (ptr <= 0)

throw new EmptyIntStackException();

return stk[ptr - 1];

}

 

public int indexOf(int x) {

for (int i = ptr - 1; i >= 0; i--)

if (stk[i] == x)

return i;

return -1;

}

 

public void clear() {

ptr = 0;

}

 

public int capacity() {

return max;

}

 

public int size() {

return ptr;

}

 

public boolean isEmpty() {

return ptr <= 0;

}

 

public boolean ifFull() {

return ptr >= max;

}

 

public void dump() {

if (ptr <= 0)

System.out.println("스택이 비어있습니다.");

else {

for (int i = 0; i < ptr; i++)

System.out.print(stk[i] + " ");

System.out.println();

}

}

}

 

 

 

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package algorithm;

 

import java.util.Scanner;

 

class IntStackTester {

public static void main(String[] args) {

Scanner stdIn = new Scanner(System.in);

IntStack s = new IntStack(64);

 

while (true) {

System.out.println("현제 데이터 수 :" + s.size() + "/" + s.capacity());

System.out.println("1.푸시 2.팝 3.피크 4.덤프 5.종료");

System.out.print(">>");

 

int menu = stdIn.nextInt();

if (menu == 5)

break;

 

int x;

switch (menu) {

case 1:

System.out.print("데이터: ");

x = stdIn.nextInt();

try {

s.push(x);

} catch (IntStack.OverflowIntStackException e) {

System.out.println("스택이 가득 찼습니다.");

}

break;

 

case 2:

try {

x = s.pop();

System.out.println("팝한 데이터는 " + x + "입니다.");

} catch (IntStack.EmptyIntStackException e) {

System.out.println("스택이 비어 있습니다.");

}

break;

 

case 3:

try {

x = s.peek();

System.out.println("피크한 데이터는 " + x + "입니다.");

} catch (IntStack.EmptyIntStackException e) {

System.out.println("스택이 비어 있습니다.");

}

break;

 

case 4:

s.dump();

break;

}

}

}

 

}

 

 

 

실행결과