Problem with part of program

I cant figure out why the complier is giving me the error: cannot convert âstd::stringâ to âintâ in return

here is part of my code:

{

for (int i= 1; i <= number; i++)

{

ones = (number % 10);

}

string ones_place(ones);

cout << number << " = " << ones << endl;

}

cin >> number;

}

cout << endl;

return 0;

}

string ones_place(int& number)

{

string ones;

if (number == 1)

ones = "one";

else if ( number ==2)

ones = "two";

else if (number ==3)

ones = "three";

else if (number ==4)

ones = "four";

else if (number ==5)

ones = "five";

else if (number ==6)

ones = "six";

else if (number ==7)

ones = "seven";

else if (number ==8)

ones = "eight";

else if (number == 9)

ones = "nine";

else if (number == 10)

ones = "ten";

else if (number == 11)

ones = "eleven";

else if (number == 12)

ones = "twelve";

else if (number == 13)

ones = "thirteen";

else if (number == 14)

ones = "fourteen";

else if (number == 15)

ones = "fifteen";

return ones;

}