stringstream into 4 variables without comma

[bluefrog]

I am struggling to figure out why the first data item is not appearing

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

int main() {

  int c_id{0};
  std::string c_last;
  double c_discount{0.0};
  float w_tax{0.0};
  std::stringstream data {"1,zzz,0.09,10.0"};

  data >> c_id >> c_last >> c_discount >> w_tax;
 
  std::cout << c_last << " " << c_discount << " "<< w_tax << "\n";
  return 0; 
}

the output from the above is:

,zzz,0.09,10.0 0 0

As you can see, the "1" is missing.
In addition, why are there additional zeros appearing on the end ?

[lastchance]

Well, you aren't outputting c_id on line 16, so there won't be a 1.

The rest of the string is going into c_last (as there are no whitespaces, but it's the only way you are going to retain commas).

Then c_discount and w_tax don't get any new values, so they stay as 0 and get output as such.

Try:

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

int main() {

  int c_id{0};
  std::string c_last;
  double c_discount{0.0};
  float w_tax{0.0};
  std::stringstream data {"1 zzz 0.09 10.0"};       // <===== use spaces, not commas

  data >> c_id >> c_last >> c_discount >> w_tax;
 
  std::cout << c_id << " " << c_last << " " << c_discount << " "<< w_tax << "\n";        // <=== output c_id as well
  return 0; 
}

[Chervil]

#include <string>
#include <iostream>
#include <sstream>

int main() {

  {
    int c_id{0};
    std::string c_last;
    double c_discount{0.0};
    float w_tax{0.0};
    
    std::stringstream data {"1,zzz,0.09,10.0"};
    
    data >> c_id >> c_last >> c_discount >> w_tax;
    
    std::cout << c_id       << " / " 
              << c_last     << " / " 
              << c_discount << " / "
              << w_tax      << "\n";   
  }
    
  {
    int c_id{0};
    std::string c_last;
    double c_discount{0.0};
    float w_tax{0.0};
    
    std::stringstream data {"1,zzz,0.09,10.0"};

    char ch;    
    data >> c_id >> ch;
    getline(data, c_last, ',');
    data >> c_discount >> ch >> w_tax;
    
    std::cout << c_id       << " / " 
              << c_last     << " / " 
              << c_discount << " / "
              << w_tax      << "\n";   
  }
}

1 / ,zzz,0.09,10.0 / 0 / 0
1 / zzz / 0.09 / 10