Why is stod "not declared in this scope"?

Question

I am trying to use stod() but I am getting the error: 'stod' was not declared in this scope.

I HAVE enabled c++ 11 and c++ 0x standards and neither have worked. As far as I can see, that is the only solution any of the other questions like his have come to.

using CodeBlocks 16.01

#include <iostream>
#include <fstream>
#include <array>
#include <string>
using namespace std;

int main()
{
double questions[5][5];
string inLine;
string buffer[5][5];
int found;
ifstream inGrade ("Grades.txt");

if (inGrade) {
    while (!inGrade.eof()){
        getline(inGrade, inLine);

        while (inLine != "\0") {
            found = inLine.find(" ");
            for (int i = 0; i < 6; i++) {
                for (int j= 0; j < found; j++) {
                    buffer[i][j] += inLine[j];
                    questions[i][j] = stod(buffer[i][j]);
                }
            }

            inLine.erase(0, found + 1);
        }
    }
}
return 0;
}