I was messing around with structs and noticed that of the following two examples, only one worked. Here they are:
struct Test
{
char *name;
int age;
};
Test p1 = { "hi", 5 };
//works
struct Test
{
char *name;
int age;
}p1;
p1 = { "hi", 5 };
//error
How come the first one compiles and the second one doesn't? Isn't p1 an object of Test either way? Thanks.
In the first example you are initializing a struct with two values in a "brace initialization." There is no support in C++ (or C) for assigning to a struct using a brace-enclosed list.
You could, however, create a new struct using brace initialization, then assign it to the old struct (p). C++ (and C) does support assignment of one struct to another of the same type.
For example, in C++11:
p1 = Test{ "hi", 5 };
p1 = (struct Test){"hi", 5"}.p = (struct XXX){.a=2, .b="def"};
The following does work with C++11:
(Compile with g++ -std=c++11 init.cpp)
#include <iostream>
struct XXX {
int a;
const char *b;
};
int main() {
XXX x;
x = XXX{1, "abc"};
// or later...
x = XXX{2, "def"};
std::cout << x.b << std::endl;
return 0;
}
