C Program For Stack Using Menu Driven Program In Switch Case

 /*Stack using array*/

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#include<stdio.h>
#include<conio.h>
void main()
{
  int a[10]={0},i,top=-1,max=10,n;
  clrscr();
  printf("\n..........MENU.........\n1.push\n2.pop\n3.display\n4.exit\n-----------------------");
  do
  {
    printf("\nenter your choice\n");
    scanf("%d",&n);
    switch(n)
    {
      case 1:
      if(top==max-1)
      printf("over flow\n");
      else
      {
 printf("enter the element\n");
 scanf("%d",&i);
 a[++top]=i;
      }
      break;
      case 2:
      if(top<0)
      printf("under flow\n");
      else
      printf("the deleted item=%d",a[top--]);
      break;
      case 3:
      if(top<0)
      printf("stack is empty\n");
      else
      {
 printf("the elements of stack are\n");
 for(i=top;i>=0;i--)
 printf("%d\n",a[i]);
      }
      break;
      case 4:
      break;
      default:
      printf("invalid choice");
      break;
      }
      }
      while(n!=4);
      }

                                                   OR

#include<stdio.h>
#include<conio.h>
#define MAX_SIZE 25
int top = -1;

void push(int);
void pop();
void display();

int stack[MAX_SIZE];

void main()
{
int y, ch;
clrscr();
do
{
printf("1.Push\n");
printf("2.Pop\n");
printf("3.Display\n");
printf("4.Exit\n");
printf("Enter the choice");
scanf("%d",&ch);

 switch(ch)
 {
 case 1:

    printf("Enter the value");
    scanf("%d",&y);

    push(y);
    break;
 case 2:
  pop();
  break;
 case 3:
 display();
  break;
 case 4:
  return;

 default:
   printf("Enter a valid option ( 1 to 4 ) \n");
   break;

 }
}while(ch!=4);
}

void push(int item)
{
 if (top==MAX_SIZE-1)
 {
    printf("Stack is full ! \n");
    return;
 }
   else
   {
      top = top + 1;
      stack[top] = item;
      printf("Pushed successfully %d \n", item);
   }
}

void pop()
{
  int x;

 if (top==-1)
 {
  printf("The stack is empty\n");
  return;
 }
 else
 {
   x = stack[top];                {
   printf("The element popped out is %d\n",x);
   top = top - 1;
 }

}

void display()
{
  int i;

  for(i=top;i>=0;i--)
  printf("%d\n",stack[i]);

}