how to brace initialize vector of custom class in C ?-CodePudding

Having this simple code:

#include <iostream>
#include <vector>
#include <string>

class Person{
public:
    Person(std::string const& name) : name(name) {}
    std::string const& getName() const {
        return name;
    }
private:
    std::string name;
};

int main(){
//    std::vector<int> ar = {1,2,3};
    std::vector<Person> persons = {"John", "David", "Peter"};
}

I am getting error:

could not convert ‘{"John", "David", "Peter"}’ from ‘<brace-enclosed initializer list>’ to ‘std::vector<Person>’

So why vector of ints is enabled to brace-initialize, but custom class with implicit constructor (with std::string) cannot? And how to enable it?

CodePudding user response：

You just need more braces:

std::vector<Person> persons = {
    {"John"}, {"David"}, {"Peter"}
};

CodePudding user response：

You can add another constructor accepting const char* to your class and it should work

class Person{
public:
    Person(const char* name): Person(std::string(name)) {}
    Person(std::string const& name) : name(name) {}
    std::string const& getName() const {
        return name;
    }
private:
    std::string name;
};

Or additional braces, like suggested in another answer.

CodePudding user response：

The issue is that you are using (C-style) string literals in the initialization list, but the vector holds std::string. One way to work around this is to pass std::string objects. Here is one way to do it:

int main(){
    using namespace std::string_literals;
    std::vector<Person> persons = {"John"s, "David"s, "Peter"s};
}

Alternatively, you can use brace initializers for each object, as suggested in another answer:

int main(){
    std::vector<Person> persons = {{"John"}, {"David"}, {"Peter"}};
}