c++ - std::map not storing any values -


i have following code:

datahandler::datahandler(){     //just call constructor default file.     datahandler(default_file); }  datahandler::datahandler(const char* filename){     refreshfromfile(filename); }  void datahandler::refresh(){     refreshfromfile(default_file); }  void datahandler::refreshfromfile(const char* filename){     std::string line, key, value;     std::ifstream file(filename);     if(file.is_open()){         while(std::getline(file, line)){             key = base64decode(line.substr(0, line.find(" ")));             value = base64decode(line.substr(line.find(" ")+1));             float floatvalue = atof(value.c_str());             values[std::string(key)] = floatvalue;             std::cout << "values[\"" << key << "\"] = " << values[key] << std::endl;         }     }     file.close(); }  float datahandler::operator[](std::string index){     if(values.find(index) == values.end()){         fprintf(stderr, "error: value %s not found, returning 0.0 \n", index.c_str());         return 0.0f;     }else{         return values[index];     } }

this works neatly, , following debug messages:

values["drive_speed"] = 1 values["grab_wheel_speed"] = 0.2 values["grab_wheel_turbo_speed"] = 0.6

if try size of map, returns 3.

but when try index anything, not found message.

#include "datahandler.hpp" #include <iostream>  int main(int argc, const char * argv[]) {     datahandler data;     data.debug();     std::cout << data["drive_speed"] << std::endl;     return 0; }

what wrong code?

datahandler::datahandler(){     //just call constructor default file.     datahandler(default_file); }

this code doesn't think does. doesn't delegate constructor call (as in java, iirr). instead, creates temporary datahandler initialised default_file, destroyed again. "correct" debug output see comes temporary.

to solve this, drop default constructor , change single-parameter 1 this:

datahandler::datahandler(const char* filename = default_file) {     refreshfromfile(filename); }

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