How Can I Rewrite Without Stod() [duplicate] - c++

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How can I rewrite my readDetails function without using stod() or strtod() in C++?
The compiler I will be using doesn't have c++11 enabled and I get
'stod' was not declared in this scope error
int readDetails(SmallRestaurant sr[])
{
//Declaration
ifstream inf;
//Open file
inf.open("pop_density.txt");
//Check condition
if (!inf)
{
//Display
cout << "Input file is not found!" << endl;
//Pause
system("pause");
//Exit on failure
exit(EXIT_FAILURE);
}
//Declarations and initializations
string fLine;
int counter = 0;
int loc = -1;
//Read
getline(inf, fLine);
//Loop
while (inf)
{
//File read
loc = fLine.find('|');
sr[counter].nameInFile = fLine.substr(0, loc);
fLine = fLine.substr(loc + 1);
loc = fLine.find('|');
sr[counter].areaInFile = stod(fLine.substr(0, loc)); //line using stod
fLine = fLine.substr(loc + 1);
loc = fLine.find('|');
sr[counter].popInFile = stoi(fLine.substr(0, loc));
fLine = fLine.substr(loc + 1);
sr[counter].densityInFile = stod(fLine); //line using stod
counter++;
getline(inf, fLine);
}
//Return
return counter;
}
Below is the text I am trying to read:
Census Tract 201, Autauga County, Alabama|9.84473419420788|1808|183.651479494869
Census Tract 202, Autauga County, Alabama|3.34583234555866|2355|703.860730836106
Census Tract 203, Autauga County, Alabama|5.35750339330735|3057|570.60159846447

Answer 1

Use std::istringstream.
std::string number_as_text("123");
int value;
std::istringstream number_stream(number_as_text);
number_stream >> value;
Edit 2: For those pedantic people:
The example below reads a double. Very similar pattern to the above reading of an integer.
std::string number_as_text("3.14159");
double pi;
std::istringstream number_stream(number_as_text);
number_stream >> pi;
You could also use a variant of sprintf.
Edit 1: Another parsing method
You could try:
std::string tract;
std::string county;
std::string state;
double value1;
char separator;
//...
std::ifstream input("myfile.txt");
//...
std::getline(input, tract, ',');
std::getline(input, county, ',');
std::getline(input, state, '|');
input >> value1;
input >> separator;
//...
input.ignore(100000, '\n'); // Ignore any remaining characters on the line
The above doesn't require separate string to number conversion.