Stack is a subclass of Vector that implements a standard last-in,
first-out stack.
Stack only defines the default constructor, which creates an empty
stack. Stack includes all the methods defined by Vector, and adds several of
its own.
Stack( )
Apart from the methods inherited from its parent class Vector, Stack
defines following methods:
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SN
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Methods with Description
|
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1
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boolean
empty()
Tests if this stack is empty. Returns true if the stack is empty, and returns false if the stack contains elements. |
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2
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Object
peek( )
Returns the element on the top of the stack, but does not remove it. |
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3
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Object
pop( )
Returns the element on the top of the stack, removing it in the process. |
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4
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Object
push(Object element)
Pushes element onto the stack. element is also returned. |
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5
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int
search(Object element)
Searches for element in the stack. If found, its offset from the top of the stack is returned. Otherwise, .1 is returned. |
Example:
The following program illustrates several of the methods supported by
this collection:
import java.util.*;
public class
StackDemo {
static void showpush(Stack st, int a) {
st.push(new Integer(a));
System.out.println("push(" + a
+ ")");
System.out.println("stack: " +
st);
}
static void showpop(Stack st) {
System.out.print("pop -> ");
Integer a = (Integer) st.pop();
System.out.println(a);
System.out.println("stack: " +
st);
}
public static void main(String args[]) {
Stack st = new Stack();
System.out.println("stack: " +
st);
showpush(st, 42);
showpush(st, 66);
showpush(st, 99);
showpop(st);
showpop(st);
showpop(st);
try {
showpop(st);
} catch (EmptyStackException e) {
System.out.println("empty
stack");
}
}
}
This would produce following result:
stack: [ ]
push(42)
stack: [42]
push(66)
stack: [42, 66]
push(99)
stack: [42, 66, 99]
pop -> 99
stack: [42, 66]
pop -> 66
stack: [42]
pop -> 42
stack: [ ]
pop -> empty
stack
