C++ input file string to float error

Question

So the example is what I want to get from my function, but I can't get atof to work because I keep getting " error: cannot convert 'std::basic_string' to 'const char*' for argument '1' to 'double atof(const char*)'". Can someone explain to me what I'm doing wrong?

Invoice2.txt:

hammer#9.95
saw#20.15
shovel#35.40

Program:

/* EXAMPLES:    *** Invoice ***
        ---------------------------- 
        hammer                $9.95

        saw                  $20.15

        shovel               $35.40
        ---------------------------- 
         3 items:           $65.50
*/


#include <iostream>
#include <string>
#include <sstream>
#include <fstream>
#include <cstdlib>
using namespace std;

// Accepts: N/A
// Returns: 0 if no error

int main(void){
    int totalItems, position;
    double totalPrice, price;
    string line, name;
    ifstream inputFile("invoice2.txt");
    cout << "*** Invoice ***" << endl << "----------------------------" <<
        endl;
    totalItems = 0;
    do{ 
        position = line.find('#');
        name = line.substr(0, position);
        price = atof(line.substr(position+1, line.length()));
        cout << name << "\t\t\t$" << price << endl;
        totalItems += 1;
        totalPrice += price;
    } while (getline(inputFile, line));
    cout << "----------------------------" << endl;
    cout << "  " << totalItems << ":\t\t\t$" << totalPrice << endl;
    return 0;
}

Answer 1

atof requires a pointer to a const char , and you give it a string . In order to make it work, you have to convert a string to a char table using the c_str() method on it.