MultiStack.cpp

#include <iostream>
#include <stack>
#include <vector>
using namespace std;


class SetOfStacks{
    vector<stack<int>> stacks;
    int threshold;
    
public:
    //Contructor, set the maximum size for each stack
    SetOfStacks(int lim){
        if(lim<2){
            throw "Couldn't initialize SetOfStacks. threshold should be greater than 1.";
        }
        
        threshold=lim;
    }
    
    //Method to insert a value to SetOfStacks
    void insert(int value){
        //Add a new stack to the top
        if(stacks.size() == 0 || stacks.back().size()==threshold){
            stacks.push_back(stack<int> ());
        }
        //Push the value to the top of top stack
        stacks.back().push(value);
    }
    
    //Method to remove a value from SetOfStacks
    void pop(){
        if(stacks.size()>0){
            //Remove the top element from the last stack
            stacks.back().pop();
            //Remove the top stack if it's empty
            if(stacks.back().size()==0) stacks.pop_back();
        }
    }
    
    //Method to read top of the SetOfStacks
    int top(){
        if(stacks.size()>0){
            return stacks.back().top();
        }
        throw "Empty stack";
    }
};



//Testing
int main(int argc, const char * argv[])
{

    SetOfStacks *hstack = new SetOfStacks(2);
    hstack->insert(-43);
    hstack->insert(3);
    hstack->insert(56);
    hstack->insert(92);
    hstack->insert(52);


    hstack->pop();
    cout<<hstack->top();
    
    return 0;
}