Reference no: EM13708280

Assignment:Create a class named SafeStack that implements a stack of strings. Use an instance of stack from <string> to hold string values and implement the same interface as the data type. However, your implementation (class) should throw an exception if an attempt is made to remove a value from an empty stack.
 

#include <stack>
#include <string>
#include <iostream>
#include <stdexcept>
using namespace std;
class FutureValueError
{
public:
    FutureValueError(const string& r);
    string& what();
private:
    string reason;
    
    };
    
    FutureValueError::FutureValueError(const string& r): reason(r) { }
   string& what()
   {
       return reason;
   }
class SafeStack
{
    
public:
   SafeStack();
   void push(string str);
   string top();
   void pop();
   int size();
   bool empty();  

private:
   stack<string> stk;
};

SafeStack::SafeStack()
{}

void SafeStack::push(string str)
{
   stk.push(str);
}

string SafeStack::top()
{
   if(stk.empty())
       throw  FutureValueError ("stack is empty!");
   else
       return stk.top();
}

void SafeStack::pop()
{
   if(stk.empty())
       throw  FutureValueError ("stack is empty!");
   else
       stk.pop();
}

int SafeStack::size()
{
   return stk.size();
}

bool SafeStack::empty()
{
   return stk.empty();
}

int main ()

{
     SafeStack mystack;
     try
            
     {
      mystack.pop();   
     }
     catch (FutureValueError& e)
     {
         cout << "Caught exception: " << e.what() << "n";
         
     }
    
    return 0;
}