How to use struct with stack?

Question

Normally when we use stack we do this....

stack<int>st;
st.push(1);
st.push(2);
st.push(3);

cout<<st.top<<"\n"  

But my question is how to push and access data when we use struct instead of int/char type variable? For example...

struct st
{
  int index, value;
};
int main()
{
  stack<st>STACK;
  /*
     code
  */

}

Now, here how can I push element in stack and access them?

Answer 1

You can push to std::stack by using Aggregate initialization , or adding a constructor to your structure or std::stack::emplace .

By using constructor:

struct st
{
  st(int _index, int _value) : index(_index), value(_value) {}
  int index, value;
};

std::stack<st> s;
s.push(st(10, 20));

By using Aggregate initialization:

std::stack<int> s;
s.push({10, 20});

To access the element simply call std::stack::top() .

st top = s.top();

or by using C++17 Structured binding declaration :

auto [index, value] = s.top();