Gfg_easy_Implement_two_stacks_in_an_array.cpp

class twoStacks
{
    int *arr;
    int size;
    int top1, top2;
    public:
    
    twoStacks(int n=100)
    {
        size = n; 
        arr = new int[n]; 
        top1 = -1; 
        top2 = size;
    }
 
    //Function to push an integer into the stack1.
    void push1(int x)
    {
        top1++;
        if(top1<(top2-1))
        arr[top1]=x;
    }
    
    //Function to push an integer into the stack2.
    void push2(int x)
    {
        top2--;
        if((top2-1)>top1)
        arr[top2]=x;
    }
    
    //Function to remove an element from top of the stack1.
    int pop1()
    {
        if(top1==-1)return -1;
        top1--;
        return arr[top1+1];
    }
    
    //Function to remove an element from top of the stack2.
    int pop2()
    {
        if(top2==size)return -1;
        top2++;
        return arr[top2-1];
       
        
    }
};