c++visual-studioconstructorinitializer

Why can't structure initialization work with array of char?


When initializing a struct using curly braces, it does not seem to work with an array of chars. I can write an equivalent constructor that works below. Is there any syntax so I don't have to write the constructor?

#include <cstdint>
#include <cstring>
using namespace std;

struct NamedLocationData {
  uint16_t offset;
  char stateName[21];
  float lat;
  float lon;
  uint32_t population;

    NamedLocationData(uint16_t offset, const char stateName[21],
                                        float lat, float lon, uint32_t population)
        :   offset(offset), lat(lat), lon(lon), population(population) {
        strncpy(this->stateName, stateName, 21);
    }

};

int main() {
    uint16_t nameOffset = 0;
    char stateName[21] = "New York";
    float lat = 40;
    float lon = -74;
    uint32_t population = 8000000;

    #if 0
    NamedLocationData temp = NamedLocationData
        {
         nameOffset, stateName, lat, lon, population
        };
    #endif
    
    NamedLocationData temp( nameOffset, stateName, lat, lon, population);
        
}

Solution

  • Default constructors are one of the special member functions. If no constructors are declared in a class, the compiler provides an implicit inline default constructor.

    I suggest you change char[] to string so that stateName will be able to get a value.

    #include <cstdint>
    #include <cstring>
    #include <string>
    using namespace std;
    struct NamedLocationData {
        uint16_t offset;
        string stateName;
        float lat;
        float lon;
        uint32_t population;
    
        NamedLocationData(uint16_t offset, string stateName,
            float lat, float lon, uint32_t population)
            : offset(offset), lat(lat), lon(lon), population(population) ,
            stateName(stateName){}
    
    
    };
    
    int main() {
        uint16_t nameOffset = 0;
        string stateName = "New York";
        float lat = 40;
        float lon = -74;
        uint32_t population = 8000000;
    
    #if 0
        NamedLocationData temp = NamedLocationData
        {
         nameOffset, stateName, lat, lon, population
        };
    #endif
        NamedLocationData temp(nameOffset, stateName, lat, lon, population);
    
        return 0;
    }
    

    Result:

    enter image description here