C++ String Stream - c++

Question

I'm just learning how to use streams in C++ and I have one question.
I thought that each stream has state true or false. I want to enter each word from the string below and 1 until there is a word, but I get an error:
cannot convert 'std::istringstream {aka std::__cxx11::basic_istringstream<char>}' to 'bool' in initialization
bool canReadMore = textIn;
It should be like:
antilope
1
ant
1
antagonist
1
antidepressant
1
What am I doing wrong?
int main() {
std:: string text = "antilope ant antagonist antidepressant";
std:: istringstream textIn(text);
for(int i = 0; i < 5; i++ ){
std:: string s;
textIn >> s;
bool canReadMore = textIn;
std::cout << s << std:: endl;
std::cout << canReadMore << std:: endl;
}
return 0;
}
``1

Answer 1

Since C++11, std::istringstream operator bool is explicit. What this means is that you must explicitly make the cast yourself:
#include <iostream>
#include <sstream>
#include <string>
int main() {
std::string text = "antilope ant antagonist antidepressant";
std::istringstream textIn(text);
for (int i = 0; i < 5; i++) {
std::string s;
textIn >> s;
bool canReadMore = bool(textIn);
std::cout << s << std::endl;
std::cout << canReadMore << std::endl;
}
return 0;
}
Output:
./a.out
antilope
1
ant
1
antagonist
1
antidepressant
1
0
Now, if you use a std::stringstream in a bool context, the conversion will be automatic. This is an idiomatic use:
#include <iostream>
#include <sstream>
#include <string>
int main() {
std::string text = "antilope ant antagonist antidepressant";
std::istringstream textIn(text);
std::string s;
while (textIn >> s) {
std::cout << s << "\n";
}
}
Output:
antilope
ant
antagonist
antidepressant