CODEWITHSUNDEEP
c++stringiteratoristream-iterator
xyzzyrz
xyzzyrz

Reputation: 16406

C++ compilation error using string and istream_iterator

When trying to compile the following:

#include <string>
#include <iterator>
#include <iostream>
using namespace std;
int main() {
  string s(istream_iterator<char>(cin), istream_iterator<char>());
  return s.size();
}

g++ 4.4.1 gives me:

main.cc: In function ‘int main()’:
main.cc:6: error: request for member ‘size’ in ‘s’, which is of non-class type ‘std::string(std::istream_iterator<char, char, std::char_traits<char>, int>, std::istream_iterator<char, char, std::char_traits<char>, int> (*)())’

According to libstdc++ docs, string has a ctor that takes a begin/end iterator pair. Why do I get this error, then?

Upvotes: 1

Views: 1711

Answers (3)

Kirill V. Lyadvinsky
Kirill V. Lyadvinsky

Reputation: 99555

You've declared a function instead of variable. Write the following to fix:

string s(istream_iterator<char>(cin), (istream_iterator<char>()));

Upvotes: 3

Jerry Coffin
Jerry Coffin

Reputation: 490058

Search for "most vexing parse", and you'll find more than you want to know.

The bottom line is that the compiler is interpreting your two parameters as specifying types instead of values. That, in turn, leads it to interpret your definition as being a declaration of a function instead.

Upvotes: 3

Fred Larson
Fred Larson

Reputation: 62053

You're accidentally declaring a function instead of instantiating a string. Try declaring variables for your istream_iterator objects and then passing those to the std::string constructor.

And here's a good read that describes exactly your problem: http://www.gotw.ca/gotw/075.htm

Upvotes: 5

Related Questions