Explanation needed

[Rakanoth]

so i exploring the documentation and i tackle something that very bother me
when i input in this program a character constant a or any.. i dont get an error.. although i should get because float price or int quantity should get a numeric value so why when i type 'a' 'b 'c' in this program its run ok

  // stringstreams
#include <iostream>
#include <string>
#include <sstream>
using namespace std;

int main ()
{
  string mystr;
  float price=0;
  int quantity=0;

  cout << "Enter price: ";
  getline (cin,mystr);
  stringstream(mystr) >> price;
  cout << "Enter quantity: ";
  getline (cin,mystr);
  stringstream(mystr) >> quantity;
  cout << "Total price: " << price*quantity << endl;
  return 0;
}

[Zhuge]

When you try to put the value into price or quantity via the stringstream, the operation just fails and leaves the variable alone.

[Rakanoth]

tnx for the explanation zhuge.