mergable_stack_cpp.cpp

#include<bits/stdc++.h> 
using namespace std; 
  
class node 
{ 
public: 
    int num; 
    node* next; 
}; 
  
class newstack 
{ 
public: 
    node* head; 
    node* tail; 
  
    newstack() 
    { 
        head=NULL; 
        tail=NULL; 
    } 
}; 
  
newstack* create() 
{ 
    newstack* stk=new newstack(); 
    return stk; 
} 
  
void push(int num,newstack* stk) 
{ 
    node* temp=new node(); 
    temp->num=num; 
    temp->next=stk->head; 
  
    if (stk->head==NULL)
	{
		stk->tail=temp; 
	}   
      
    stk->head=temp; 
} 
  
int pop(newstack* ms) 
{ 
    if (ms->head==NULL) 
	{ 
        cout<<"stack underflow"<<endl; 
        return 0; 
    } 
    else 
	{ 
        node* temp=ms->head; 
        ms->head=ms->head->next; 
        int popped=temp->num; 
        delete temp; 
        return popped; 
    } 
} 
  
void merge(newstack* ms1,newstack* ms2) 
{ 
   if(ms1->head==NULL) 
   { 
       ms1->head=ms2->head; 
       ms1->tail=ms2->tail;  
       return; 
   } 
     
   ms1->tail->next=ms2->head; 
   ms1->tail=ms2->tail;  
} 
  
void print(newstack* ms) 
{ 
    node* temp=ms->head; 
    while (temp!=NULL) 
	{ 
        cout<<temp->num<<" "; 
        temp=temp->next; 
    }  
} 
  
int main() 
{ 
    newstack* stack1=create(); 
    newstack* stack2=create(); 
    
    int n1,n2,temp;
    cout<<"enter sizes of both the stacks"<<endl;
    cin>>n1>>n2;
    cout<<"enter elements of 1st stack:"<<endl;
    for(int i=1;i<=n1;i++)
    {
    	cin>>temp;
    	push(temp,stack1);
	}
	cout<<"enter elements of 2nd stack:"<<endl;
    for(int i=1;i<=n2;i++)
    {
    	cin>>temp;
    	push(temp,stack2);
	}
	
	merge(stack1,stack2);
	cout<<"The result after merging both stacks:"<<endl; 
    print(stack1); 
}