Multiple Stack

Implementation of multiple stacks in a single linear array

//Include the necessary header files

#define SIZE 12 //Size of array(Vary as per need)

#define MAX 4 //Maximum number of stacks to store(vary as per need)

typedef struct

{

     int stk[SIZE];

     int top[MAX];

     int boundary[MAX];

}STACK;

void push();

void pop();

void display();

int main()

{

     STACK s;

     int choice, i, j, n;

     s.top[0] = s.boundary[0]=-1;

     printf("\nEnter the number of stacks you want to implement: ");

     scanf("%d", &n);

     for(i=1 ; i < n ; i++)

     {

            s.top[i] = s.boundary[i] = ((SIZE/n)*i)-1;

     }

     s.boundary[n] = SIZE-1;

     do

     {

            printf("\n\nOperation on three stacks:");

            printf("\n\n1.) Push");

            printf("\n2.) Pop");

            printf("\n3.) Display");

            printf("\n4.) Exit");

            printf("\n\nEnter your choice: ");

            scanf("%d", &choice);

            switch( choice )

            {

case 1: printf("\nEnter the stack number in which element is to be pushed(1- %d): ", n);

scanf("%d", &j);

if(j>n || j<1)

break;

push(&s, j);

break;

case 2: printf("\nEnter the stack number to pop element from(1-%d): ", n); scanf("%d", &j);

if(j>n || j<1);

break;

pop(&s, j);

break;

case 3: printf("\nEnter the stack number to display(1-%d): ", n);

scanf("%d", &j);

if(j>n || j<1)

break;

display(s, j);

break;

case 4: break;

default: printf("\nInvalid choice! Enter again.");

}

     }while(choice!=4);

     getch();

}

void push(STACK *p, int j)

{

  int i;

i=j-1;

if(p->top[i] == p->boundary[j])

{

printf("\nStack%d is overflow", j);

}

else

{

(p->top[i])++;

printf("\nEnter the element to push: ");

scanf("%d", &p->stk[p->top[i]]);

}

}

void pop(STACK *p, int j)

{

int i;

i=j-1;

if(p->top[i] == p->boundary[i])

{

printf("\nStack%d is underflow", j);

}

else

{

printf("\nPopped element: %d", p->stk[(p->top[i])--]);

}

}

void display(STACK s, int j)

{

int i, k;

i=j-1;

if(s.top[i] == s.boundary[i])

{

printf("\nStack%d is empty", j);

}

else

{

printf("\nStack%d is: \n", j);

for(k=s.top[i]; k>s.boundary[i]; k--)

{

printf("\n%d", s.stk[k]);

}

}
}