# 陣列實現堆疊

#### 1. 在堆疊中新增元素(推播操作)

``````開始
if top = n 那麼堆疊滿
top = top + 1
stack (top) : = item;

``````

C語言中推播演算法的實現 -

``````void push (int val,int n) //n is size of the stack
{
if (top == n ){
printf("Overflow\n");
}else
{
top = top + 1;
stack[top] = val;
}
}
``````

#### 2. 從堆疊中刪除元素(彈出操作)

``````開始
if top = 0 那麼堆疊為空;
item := stack(top);
top = top ? 1;

``````

``````int pop ()
{
if(top == -1)
{
printf("Underflow");
return 0;
}
else
{
return stack[top -- ];
}
}
``````

#### 3. 存取堆疊的每個元素(Peek操作)

Peek操作涉及返回堆疊頂部存在的元素但不刪除它。如果嘗試返回已經空堆疊中的頂部元素，則可能發生下溢情況。

``````開始
if top = -1 那麼堆疊
item = stack[top]
return item

``````

``````int peek()
{
if (top == -1)
{
printf("Underflow");
return 0;
}
else
{
return stack [top];
}
}
``````

``````#include <stdio.h>
int stack[100], i, j, choice = 0, n, top = -1;
void push();
void pop();
void show();
void main()
{

printf("Enter the number of elements in the stack ");
scanf("%d", &n);
printf("*********Stack operations using array*********");
printf("----------------------------------------------\n");
while (choice != 4)
{
printf("Chose one from the below options...\n");
printf("1.Push\n2.Pop\n3.Show\n4.Exit");
scanf("%d", &choice);
switch (choice)
{
case 1:
{
push();
break;
}
case 2:
{
pop();
break;
}
case 3:
{
show();
break;
}
case 4:
{
printf("Exiting....");
break;
}
default:
{
}
};
}
}

void push()
{
int val;
if (top == n)
printf("Overflow");
else
{
printf("Enter the value?");
scanf("%d", &val);
top = top + 1;
stack[top] = val;
}
}

void pop()
{
if (top == -1)
printf("Underflow");
else
top = top - 1;
}
void show()
{
for (i = top;i >= 0;i--)
{
printf("%d\n", stack[i]);
}
if (top == -1)
{
printf("Stack is empty");
}
}
``````

``````import java.util.Scanner;

class Stack {
int top;
int maxsize = 10;
int[] arr = new int[maxsize];

boolean isEmpty() {
return (top < 0);
}

Stack() {
top = -1;
}

boolean push(Scanner sc) {
if (top == maxsize - 1) {
System.out.println("Overflow !!");
return false;
} else {
System.out.println("Enter Value");
int val = sc.nextInt();
top++;
arr[top] = val;
System.out.println("Item pushed");
return true;
}
}

boolean pop() {
if (top == -1) {
System.out.println("Underflow !!");
return false;
} else {
top--;
System.out.println("Item popped");
return true;
}
}

void display() {
System.out.println("Printing stack elements .....");
for (int i = top; i >= 0; i--) {
System.out.println(arr[i]);
}
}
}

public class Stack_Operations {
public static void main(String[] args) {
int choice = 0;
Scanner sc = new Scanner(System.in);
Stack s = new Stack();
System.out.println("*********Stack operations using array*********\n");
System.out.println("------------------------------------------------\n");
while (choice != 4) {
System.out.println("Chose one from the below options...\n");
System.out.println("1.Push\n2.Pop\n3.Show\n4.Exit");
choice = sc.nextInt();
switch (choice) {
case 1: {
s.push(sc);
break;
}
case 2: {
s.pop();
break;
}
case 3: {
s.display();
break;
}
case 4: {
System.out.println("Exiting....");
System.exit(0);
break;
}
default: {
}
}
;
}
}
}
``````

``````using System;

public class Stack
{
int top;
int maxsize=10;
int[] arr = new int[10];
public static void Main()
{
Stack st = new Stack();
st.top=-1;
int choice=0;
Console.WriteLine("*********Stack operations using array*********");
Console.WriteLine("----------------------------------------------\n");
while(choice != 4)
{
Console.WriteLine("Chose one from the below options...\n");
Console.WriteLine("1.Push\n2.Pop\n3.Show\n4.Exit");
switch(choice)
{
case 1:
{
st.push();
break;
}
case 2:
{
st.pop();
break;
}
case 3:
{
st.show();
break;
}
case 4:
{
Console.WriteLine("Exiting....");
break;
}
default:
{
break;
}
};
}
}

Boolean push ()
{
int val;
if(top == maxsize-1)
{

Console.WriteLine("Overflow");
return false;
}
else
{
Console.WriteLine("Enter the value?");
top = top +1;
arr[top] = val;
Console.WriteLine("Item pushed");
return true;
}
}

Boolean pop ()
{
if (top == -1)
{
Console.WriteLine("Underflow");
return false;
}

else

{
top = top -1;
Console.WriteLine("Item popped");
return true;
}
}
void show()
{

for (int i=top;i>=0;i--)
{
Console.WriteLine(arr[i]);
}
if(top == -1)
{
Console.WriteLine("Stack is empty");
}
}
}
``````