Question about storing array in a std::vector in C++

Question

I am unclear about the following.

First, this code compiles fine:

#include 

typedef struct{
    int x1,x2,x3,x4;
}  ints;

typedef std         


        

Answer 1

error: ISO C++ forbids initialization in array new
error: array must be initialized with a brace-enclosed initializer
error: invalid array assignment
error: request for member ‘~int [4]’ in ‘* __p’, which is of non-class type ‘int [4]’

To understand one of the errors, imagine the following:

void main() {
    int a[4] = {0,1,2,3};
    int b[4] = a;
}

As opposed to:

typedef struct{
    int x1,x2,x3,x4;
}  ints;

int main()
{
    ints a;
    ints b = a;
}

Or even:

typedef struct{
    int x[4];
}  ints;

int main()
{
    ints a;
    ints b = a;
}

C/C++ arrays cannot be copied via the assignment operator, though structs containing arrays can be.
So an easy fix is to do:

typedef struct{
        int x[4];
}  ints;

typedef std::vector vec;

int main(){
        vec v;
        ints a = { {0,1,2,3} };
        v.push_back(a);
}