Another string problem

[halo3d]

well i got another problem..
in this thing when user enters a long string like

this is a string


it comes out in the file like

this
is
a
string

any way .. can u guys tell me how i can make it so that it stores the input into string variable only when user presses enter and not space...

im uploading the whole project this time..

[wtd]

When you use the extraction operator to obtain a string from an input stream, it stops at the first whitespace. To read an entire line, you must use the std::getline function.

[bugzpodder]

don't forget to becareful when mixing cin with getline. see post named random string line

[wtd]

Could you explain what you mean about mixing cin and getline? I don't think I'm seeing the issue you are.

[halo3d]

so how exactly do i use std::getline in my program here? i mean whats the syntax and stuff... any example?

[ericfourfour]

I would try

code:

input = std::getline ();

It wouldn't kill you to use Google every now and then.

[wtd]

http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/namespacestd.html#a645

[halo3d]

ericfourfour wrote:

I would try

code:

input = std::getline ();

It wouldn't kill you to use Google every now and then.

Why thanx ericfourfour i would use google from now rather than this site... thanx for the "little" help..

bye

[bugzpodder]

wtd wrote:

Could you explain what you mean about mixing cin and getline? I don't think I'm seeing the issue you are.

cin>>x misses the newline char. getline chews everything including the newline char. Hence a getline after a cin will usually result in an empty string being fetched, most likely not the intended behaviour. I don't see how one could get around this without managing newlines explicitly and very carefully.

Input

code:

56 this is a new line

code:

cin >> num; getline(cin, str); cout<<num<<endl<<str<<endl;

Output:

code:

56

[wtd]

This just calls for input validation.

Maybe something like:

code:

struct non_empty_string {    std::string str;    non_empty_string(); }; std::istream& operator>>(std::istream& in, non_empty_string& s); std::ostream& operator<<(std::ostream& out, const non_empty_string& s) int main() {    std::string x;    non_empty_string nes;    cin >> x >> nes;    cout << x   << endl         << nes << endl;    } non_empty_string::non_empty_string() : str("") { } std::istream& operator>>(std::istream& in, non_empty_string& s) {    do  { std::getline(in, s.str); } while (s.str == "");    return in; } std::ostream& operator<<(std::ostream& out, const non_empty_string& s) {    return out << s.str; }

[bugzpodder]

one more thing to be careful of: getline doesn't actually get the newline, so you must eat up the newline youself!