2StacksInAnArrays.cpp

/*The structure of the class is
class twoStacks
{
    int *arr;
    int size;
    int top1, top2;
public:
   twoStacks(int n=100){size = n; arr = new int[n]; top1 = -1; top2 = size;}
 
   void push1(int x);
   void push2(int x);
   int pop1();
   int pop2();
};
*/


/* The method push to push element into the stack 2 */
void twoStacks :: push1(int x)
{ 
     arr[++top1] = x;

}
   
/* The method push to push element into the stack 2*/
void twoStacks ::push2(int x)
{
    arr[--top2] = x;

}
   
/* The method pop to pop element from the stack 1 */
//Return the popped element
int twoStacks ::pop1()
{
     if(top1 == -1)
         return -1;
     return arr[top1--];     
}

/* The method pop to pop element from the stack 2 */
//Return the popped element
int twoStacks :: pop2()
{
    if(top2 == size)
         return -1;
     return arr[top2++];  

}