How to input a string like "The code Project" to a string type using istream?

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Hi guys,
my problem is when I was trying to enter a book name, I won't success, codes like below:

C#

class SalseItem
{
    friend istream& operator>>(istream& is,SalseItem& si){
        cout<<"Please input the book name:"<<endl;
        is>>si.name;
        cout<<"Please input the number:"<<endl;
        is>>si.num;
        cout<<"Please enter the price:"<<endl;
        is>>si.price;
        if(!is)
           si = SalesItem();//default constructor
        return is;
    }
    ...
}

int main(int argc, char* argv[])
{
	SalseItem si;
	cin>>si;//I enter "The code project" + key_return,then si.name == "The" ,not "The code project";
	cout<<si;
	return 0;
}

How can I achieve the job ,inputing exactly "The code project" to a si.name?

[edit]Spurious code blocks removed - OriginalGriff[/edit]

Posted 25-Mar-11 20:37pm

scu_sundy

Updated 25-Mar-11 21:32pm

OriginalGriff

v2

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Sandeep Mewara 26-Mar-11 2:49am

Not clear. Can you elaborate a little?

2 solutions

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Alain Rist · Answer 1 · 2011-03-25T21:38:00

Solution 2

Hi,
When you write is>>si.name; cin extraction stops reading as soon as it finds any blank space character.
In order to get entire lines, use the function getline:

class SalseItem
{
    friend istream&
    operator>>(istream& is,SalseItem& si)
    {
        cout<<"Please input the book name:"<<endl;
        getline (cin, si.name);
        // ...

cheers,
AR

Posted 25-Mar-11 21:38pm

Alain Rist

Comments

scu_sundy 26-Mar-11 3:47am

I'm afraid the input will never go on.

OriginalGriff 26-Mar-11 3:51am

...And you gave an example! 5!

scu_sundy 26-Mar-11 3:55am

I found a way like below, space will be accepted, key of return will end my input:
char c;
while (!is.eof())
{
if((c = is.get()) != '\n')
si.name += c;
else
break;
}

Emilio Garavaglia 26-Mar-11 4:03am

That's exactly what getline does

scu_sundy 26-Mar-11 4:12am

Hi Emilio, I had tried Alain's way just now, but I had to hit enter twice to end inputing a book name,this was not nice to me.

OriginalGriff · Answer 2 · 2011-03-25T21:37:00

Solution 1

If you look at the definition for istream>>[^], you will see the problem:
"Extraction ends when the next character is either a valid whitespace or a null character, or if the End-Of-File is reached."

You may want to use getline[^] instead.

Posted 25-Mar-11 21:37pm

OriginalGriff

Comments

Alain Rist 26-Mar-11 3:46am

You were quicker :)

OriginalGriff 26-Mar-11 3:50am

...but I'm not sure the OP understood either of us...
:laugh:

scu_sundy 26-Mar-11 3:52am

Thank you griff!
Shall we try some kind of compartmentation symbol change, will istream accept space after any settings?

OriginalGriff 26-Mar-11 3:56am

AFAIK, no - and the method you added on Alains' reply is the same as using getline...

scu_sundy 26-Mar-11 4:08am

Not so, if I use 'getline' like he had presented below, I had to click enter twice, it's not what I need.