Page 499 - Computer science 868 Class 12
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Let us illustrate the push and pop operations in Stack with the following Java programs.
Program 1 Stack is a kind of data structure which can store elements with the restriction that an element
can be added or removed from the top only. The details of class Stack are given below.
Class name : Stack
Data Members
a[] : an array to hold numbers
size : the maximum capacity of the string array
top : the index of the topmost element of the stack
Member Functions
Stack(int x) : constructor to initialise size = x and top = -1
void push (int n) : to push number ‘n’ into the stack. If the stack is full, display
the message “overflow”
void pop() : to remove an element from the top of the stack and display
it. If the stack is empty, display the message “underflow”
void display() : to display the elements of the stack
Specify class Stack giving details of the constructor(), void push (int n), void pop() and void
display().
1 import java.util.*;
2 class Stack
3 { int a[];
4 int size,top;
5 Stack(int x)//constructor
6 { size=x;
7 top=-1;
8 a=new int[size];
9 }
10 void push(int n) // push
11 { if(top==size-1) // if stack is full
12 System.out.println("Stack full.........overflow");
13 else
14 a[++top]=n; // increase top by 1 and push n to stack
15 }
16 void pop() //pop
17 { if(top<0) // if stack is empty
18 { System.out.println("Stack empty....underflow");
19 }
20 else
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Data Structures 497

