text file not working?

Im new to c++ and learning text file processing and for some reason my text file isnt working help code below:

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
       ofstream outFile("c:\numbers\numbers.txt",  ios::out);
       outFile << 100 << endl;
       outFile << 90 << endl;
       outFile << 80 << endl;
       outFile << 70 << endl;
       outFile.close();
       return 0;
}