multi_stack.c

#include <stdio.h>
#define max 10
int top1, top2, b1, b2, arr[max];
void push();
void pop();
void display();
void main()
{
	int ch;
	top1=b1=-1;
	top2=b2=max-1/2;
	do{
		printf("\n 1:push\n 2:pop\n 3:display\n 4:exit\n choice:");
		scanf("%d", &ch);
		switch (ch)
		{
			case 1:push();
				break;
			case 2:pop();
				break;
			case 3:display();
				break;
			case 4:printf("exiting from program\n");
				break;
			default:printf("wrong choice\n");
				break;
		}
	}while(ch!=4);
}

void push()
{
	int x,n, ch;
	printf("enter a no \n");
	scanf("%d",&x);
	printf("\n press 1 to push in stack1 or press 2 for stack2:");
	scanf("%d",&ch);
	if(ch==1){
		if(top1==b2)
		{
			printf("stack overflow \n");
			return;
		}
	else
		arr[++top1]=x;
	}
	if(ch==2)
	{
		if(top2==n-1)
		{
			printf("stack overflow \n");
			return;
		}
		else
			arr[++top2]=x;
	}
}

void pop()
{
	int y,ch;
	printf("\n press 1 to pop from stack1 or press 2 for stack2");
	scanf("%d",&ch);
	if(ch==1)
	{
		if(top1==-1)
		{
			printf("stack underflow\n");
			return;
		}
		y=arr[top1];
		arr[top1--]=0;
	}
	else{
		if(top2==b2)
		{
			printf("stack underflow\n");
			return;
		}
		y=arr[top2];
		arr[top2--]=0;
	}
	printf("\n%d element is successfully poped from stack \n", y);
	return;
}

void display()
{
	int i;
	if (top1 == -1)
		printf("stack 1 is empty \n");
	else{
		printf("elements of Stack 1 are : \n");
		for (i = 0; i<= top1; i++)
			printf("%d\n",arr[i]);
	}
	if(top2 == b2)
		printf("stack 2 is empty \n");
	else
	{
		printf("elements of Stack 2 are : \n");
		for (i =b2+1; i<=top2; i++)
			printf("%d\n",arr[i]);
	}
	return ;
}