getline(cin, aString) receiving input without another enter

Question

My code looks like this,

string aString;
cin >> aString;
cout << \"This is what cin gets:\" << aString << endl;
getline(cin, aString)         


        

Answer 1

"cin >> x" doesn't consume the newline character from the input stream, so the next line you retrieve with getline will contain an empty string. One way to solve this is to use getline to retrieve input line by line and use a stringstream to tokenize each line. After you've extracted all input from the stringstream, the key thing is to call stringstream::clear() to clear the EOF flag set on the stringstream to be able to reuse it later in the code.

Here's an example:

#include 
#include 
#include 

using namespace std;

int main() {
    string line;
    stringstream ss;
    getline(cin, line);
    ss << line;
    int x, y, z;
    //extract x, y, z and any overflow characters
    ss >> x >> y >> z >> line;
    ss.clear();
    //reuse ss after clearing the eof flag
    getline(cin, line);
    ss << line;
    //extract new fields, then clear, then reuse
    //...
    return 0;
}

Depending on the length of each input line, getting the whole line at a time and processing it in-memory is probably more efficient than doing console IO on every token you want to extract from the standard input.