CODEWITHSUNDEEP
c++oopstdin
Luke
Luke

Reputation: 317

std::cin - can you have one input put into two different variables?

Hi I am trying to read input from the user once and then pass this value into two different types of variables is this possible?

I need the value to be passed into an integer variable which is required for calculations and also a string so I can add the data to the formatted date which is a string variable.

Here is he code which I have tried which doesn't work.

cin >> daymonth,dayofmonth;

Any help would be greatly appreciated, I am programming in OOP if this is of any relevance.

Upvotes: 1

Views: 8434

Answers (3)

P0W
P0W

Reputation: 47854

You can overload <<

#include<sstream>
//..
class X{

    int daymonth;
    std::string dayofmonth;

    friend std::istream& operator >> (std::istream& is, X& m)
    {

        is >> m.daymonth;
        std::stringstream ss;
        ss << m.daymonth;
        m.dayofmonth = ss.str();
        return is;
    }

    friend std::ostream& operator << (std::ostream& os, const X& m)
    {
        return os << m.daymonth << ":" << m.dayofmonth;

    }
};

And then

 X x;  
 std::cin >> x;
 std::cout << x;

Upvotes: 0

Thomas Matthews
Thomas Matthews

Reputation: 57749

Try copying / assignment:

cin >> daymonth;
dayofmonth = daymonth;

In the performance of your program, using multiple lines or multiple statements is negligible.

Concentrate on making the program work correctly and robustly.

Edit 1: dayofmonth is a string. 

cin >> dayofmonth;
istringstream s(dayofmonth);
s >> daymonth;

Upvotes: 0

Oswald
Oswald

Reputation: 31685

You cannot read into two variables simultaneously. The type of variable that you read into determines how far to read. For example, reading into a string stops at white space while reading into an integer stops at the first non-integer character. Reading into two variables simultaneously would make it ambiguous where the next reading operation starts.

Read into an integer and then convert the integer to a string (e.g. using std::to_string).

Upvotes: 3

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