C++ String to Double Array

[BrownZeus]

Hey there!

 

Learning C++ on the fly for a school assignment.

I have to read data from a csv and crate objects with it. I have Java experience so I already have my class coded that has the fields from the csv file as fields for the objects.

Now here's where I'm having just a tiny hiccup:

 

The CSV file format is as such

 

val1,val2,val3,{array of doubles},val4

 

I have my code written already that reads the file line by line and reads the data successfully (tested via cout all the fields to the console.)

 

Since the array of doubles get read in as string i need to convert that string into an array of doubles, how do I accomplish this?

[TheOcularMan]

10 minutes ago, BrownZeus said:

Hey there!

 

Learning C++ on the fly for a school assignment.

I have to read data from a csv and crate objects with it. I have Java experience so I already have my class coded that has the fields from the csv file as fields for the objects.

Now here's where I'm having just a tiny hiccup:

 

The CSV file format is as such

 

val1,val2,val3,{array of doubles},val4

 

I have my code written already that reads the file line by line and reads the data successfully (tested via cout all the fields to the console.)

 

Since the array of doubles get read in as string i need to convert that string into an array of doubles, how do I accomplish this?

http://www.cplusplus.com/reference/cstdlib/strtod/

[BrownZeus]

2 minutes ago, TheOcularMan said:

http://www.cplusplus.com/reference/cstdlib/strtod/

Helpful but not 100%. This is for single values. I need to convert a whole strong into an array.

 

"{2.5, 3.5, 36.4} into a double array

[TheOcularMan]

39 minutes ago, BrownZeus said:

Helpful but not 100%. This is for single values. I need to convert a whole strong into an array.

 

"{2.5, 3.5, 36.4} into a double array

#include <iostream>
#include <stdlib.h>
#include <string.h>

using namespace std;

int main()
{
    cout << "Goodbye world!" << endl;

    const int _size = 10;
    double _array[_size];

    char _string[] = "1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9 666.666";
    char *_sz;

    for(int i = 0; i < _size; i++)
    {
        _array[i] = strtod(_string, &_sz);
        strcpy(_string, _sz);
        cout << i << ": " << _array[i] << endl;
    }
    return 0;
}

 

[Unimportant]

8 hours ago, BrownZeus said:

"{2.5, 3.5, 36.4} into a double array

Into a vector I'll assume, as array sizes are fixed at compile time.

 

#include <iostream>
#include <string>
#include <algorithm>
#include <sstream>
#include <iterator>
#include <vector>

int
main()
{
    std::string exampleString = "{2.5, 3.5, 36.4}";

    //Test if string begins with { and ends with }.
    if (exampleString.front() != '{' || exampleString.back() != '}')
    {
        std::cout << "String does not begin with '{' and/or end with '}'\n";
        return 1;
    }

    //Replace {} and comma's with whitespace.
    exampleString.front() = exampleString.back() = ' ';
    std::replace(exampleString.begin(), exampleString.end(), ',', ' ');

    //Create stringstream from string.
    auto iss = std::istringstream(exampleString);

    //Create vector of doubles from stringstream.
    const auto doublesVector = std::vector<double>(std::istream_iterator<double>(iss),
                                                   std::istream_iterator<double>());

    //Check for errors.
    if (!iss && !iss.eof())
    {
        std::cout << "Error parsing string.\n";
        return 2;
    }

    //Print result.
    for (const auto d : doublesVector)
    {
        std::cout << d << ' ';
    }

    return 0;
}