Accepting string inputs?

Question

why does a work but not b?
int main() {
string a = "I am learning C++";
string b;
cin >> b; //user inputs I am learning C++
cout << a << endl;
cout << b << endl ;
return 0;
}

output is ....
I am learning C++
I

why does b not output the full sentance?

Answer 1

I have not much eperience with c++ but the problems seems to be the space. Once you hit space the string cuts. So in the cin only goes a word, not a sentance.

I found the answer:
This only reads in the next token. In C++ iostreams, tokens are separated by whitespace, so you get the first word.

You probably want getline, which reads an entire line into a string:
getline(cin, str);

Answer 2

because cin read only one word, it ignores the white space and the rest. So you mustn't write cin>>b, but
getline(cin, b);