Definition
A stack is a basic computer science data structure and can be defined in an abstract, implementation-free manner,
or it can be generally defined as a linear list of items in which all additions and deletion are restricted to one end that is Top.Stack Using Array And Class Example Program
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class Stack {
private int top;
private int item[];
Stack(int size) {
top = -1;
item = new int[size];
}
void pushItem(int data) {
if (top == item.length - 1) {
System.out.println("Stack is Full");
} else {
item[++top] = data;
System.out.println("Pushed Item :" + item[top]);
}
}
int popItem() {
if (top < 0) {
System.out.println("Stack Underflow");
return 0;
} else {
System.out.println("Pop Item : " + item[top]);
return item[top--];
}
}
}
class StackExample {
public static void main(String[] args) throws IOException {
Stack stk = new Stack(5);
boolean yes=true;
int choice;
BufferedReader is = new BufferedReader(new InputStreamReader(System.in));
do{
System.out.println("1).Push\n2).Pop\n3).Exit\n\nEnter Choice");
choice = Integer.parseInt(is.readLine());
switch(choice)
{
case 1: System.out.println("Enter Push Item: ");
stk.pushItem(Integer.parseInt(is.readLine()));
break;
case 2: stk.popItem();break;
case 3: yes = false;break;
default: System.out.println("Invalid Choice");
}
}while(yes==true);
}
}
Sample Output
Output is:
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
14
Pushed Item :14
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
567
Pushed Item :567
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
67
Pushed Item :67
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
789
Pushed Item :789
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
56
Pushed Item :56
1).Push
2).Pop
3).Exit
Enter Choice
1
Enter Push Item:
99
Stack is Full
1).Push
2).Pop
3).Exit
Enter Choice
2
Pop Item : 56
1).Push
2).Pop
3).Exit
Enter Choice
2
Pop Item : 789
1).Push
2).Pop
3).Exit
Enter Choice
2
Pop Item : 67
1).Push
2).Pop
3).Exit
Enter Choice
2
Pop Item : 567
1).Push
2).Pop
3).Exit
Enter Choice
2
Pop Item : 14
1).Push
2).Pop
3).Exit
Enter Choice
2
Stack Underflow
1).Push
2).Pop
3).Exit
Enter Choice
3
