Unable to input (cin) when using strings

There is no error code, that's the problem, when I use the code below.
Everything worked fine until I added the code that is between the @@@@@@@@@@

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

int main()
{
cout << "Hello World" << endl;
int a=5, b=20, c, d, e, f, age;
cout << "20-5=";
cout << b-a << endl;
string mystr;
string mystr2;
cout << "Hi, what's your first name?" << endl;
getline (cin, mystr);
cout << "Hi " << mystr << ", what a nice name!" << endl;
cout << "How old are you?" << endl;
cin >> age;
c=age*365;
d=c*24;
e=d*60;
f=e*60;
cout << "You have lived about:" << endl << age << " years." << endl << c << " days." << endl << d << " hours." << endl << e << " minutes." << endl << f << " seconds." << endl;
int i;
cout << "Enter a number: ";
cin >> i;
cout << "The number you entered is " << i << " and it's double is " << i*2 << endl << endl;

@@@@@@@@@@
float price=0;
int quantity=0;
cout << "Enter price: ";
getline (cin,mystr2);
stringstream(mystr2) >> price;
cout << "Enter quantity: ";
getline (cin,mystr2);
stringstream(mystr2) >> quantity;
cout << "Total price: " << price*quantity <<
endl;
@@@@@@@@@@
system("pause");
return 0;
}



The code on itself works, tested in a seperate project using only that code, but when including it in this code the output is that when asking for the price and quantity I see:
Price:Quantity:
Then I can only input something after the quantity, meaning that the result (price) is always 0 as I just can't input to price.

Anyone knows what I'm doing wrong?

This is a test program, I know there are different ways to do this but just this on itself isn't working and I'm trying for hours..

You have ...

Code:

---

cin >> i;

// other code ... and then

getline (cin,mystr2);

---

This is a common problem when mixing operator >> with getline.

After the first cin (cin >> i), the ENTER ('\n') is still
in the input stream buffer. The getline then reads an
empty string (since it stops reading after the first '\n'
that it encounters). One way around this is to do an ignore
after the operator >> ...

Code:

---

cin >> i;
cin.ignore(1000,'\n');

---

In this case, why are you reading the price and quantity
into strings and then using stringstream ? You can use
operator >> directly ...

Code:

---

cin >> price;

//

cin >> quantity;

---

I run it and entered only one name. Why is that app of yours required and additional cr/lf line ?
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