expected identifier before string constant - c++

Question

Having a program like this:
#include <iostream>
#include <string>
using namespace std;
class test
{
public:
test(std::string s):str(s){};
private:
std::string str;
};
class test1
{
public:
test tst_("Hi");
};
int main()
{
return 1;
}
…why am I getting the following when I execute
g++ main.cpp
main.cpp:16:12: error: expected identifier before string constant
main.cpp:16:12: error: expected ‘,’ or ‘...’ before string constant

Answer 1

You can not initialize tst_ where you declare it. This can only be done for static const primitive types. Instead you will need to have a constructor for class test1.
EDIT: below, you will see a working example I did in ideone.com. Note a few changes I did. First, it is better to have the constructor of test take a const reference to string to avoid copying. Second, if the program succeeds you should return 0 not 1 (with return 1 you get a runtime error in ideone).
#include <iostream>
#include <string>
using namespace std;
class test
{
public:
test(const std::string& s):str(s){};
private:
std::string str;
};
class test1
{
public:
test1() : tst_("Hi") {}
test tst_;
};
int main()
{
return 0;
}

Answer 2

There is another and more simplified way of doing what you want:Just change your statement from test tst_("Hi"); to test tst_{"Hi"}; and it will work. Below is the modified code and it works as expected.
#include <iostream>
#include <string>
using namespace std;
class test
{
public:
test(std::string s):str(s){cout<<"str is: "<<s;}
private:
std::string str;
};
class test1
{
public:
test tst_{"Hi"};
};
int main()
{ test1 obj;
return 0;
}
Note that i have just changed test tst_("Hi"); to test tst_{"Hi"}; and everything else is exactly the same. Just for confirmation that this works i have added one cout to check that it initialize the str variable correctly. I think this one line solution is more elegant(at least to me) and and up to date with the new standard.