Questions tagged [member-initialization]
121 questions
3
votes
2 answers
Why can't access to enum here?
Here's my code/namespace:
namespace myNamespace {
enum MyType {
ASD1,
ASD2,
ASD3
};
struct MyClass {
MyType mMyType;
MyClass(MyType myType = MyType::ASD1) : mMyType(myType) {
}
};
}
Now if I try, within another struct,…
markzzz
- 47,390
- 120
- 299
- 507
3
votes
1 answer
How to fix derived class giving 'declaration has no storage class or type specifier' error?
I am trying to initialize a base class variable in a derived class, but instead, I am given an error:
"this declaration has no storage class or type specifier"
I have been tinkering with C++ inheritance and derived classes in Visual Studio. I made…
tensofturtles
- 37
- 1
- 6
3
votes
1 answer
Which part of standard determines priority of in-place member vs initializer list?
I just made a sample, which from my personal point of view should not compile, or at least give a warning, but Visual Studio 2017 does not give any warnings. The sample is following:
#include
struct Foo {
Foo(int i) { throw…
Rudolfs Bundulis
- 11,636
- 6
- 33
- 71
3
votes
4 answers
Disable default class member initialization before constructor code
In C++, any member of a class which is not constructed in a member initialization list is default constructed before the containing class's constructor is executed. However, this appears to be very wasteful if that member variable is just going to…
Marco Merlini
- 875
- 7
- 29
3
votes
2 answers
Member initializer list. Order of arguments evaluation
Example of a code with a member initializer list.
#include
struct Throwable
{
Throwable()
{
throw "Exception!";
}
};
struct A
{
A() : t(Throwable()), i(new int()) {}
Throwable t;
std::unique_ptr…
Iurii Popov
- 53
- 4
3
votes
2 answers
Better way to organize initializer lists in constructors
Sometimes there is a need to do some processing on the class constructor arguments before initializing const members or those not having a default constructor.
For instance, in Java I can do this (don't ask why, it's just an example):
class A
{
…
Alex
- 1,165
- 2
- 9
- 27
3
votes
2 answers
Aggregate Member Initialization in C++14
Having this structure:
struct A {
struct B {
int a = 21;
int b;
int c = 22;
int d;
int e = 23;
};
B b1 = { 11, 12 };
B b2 = { 11, 12, 13 };
int x;
};
And declaring:
A a = { { 1, 2, 3, 4…
J L
- 563
- 3
- 17
3
votes
2 answers
C++ - Mixing default member initializers and member initialization lists - bad idea?
This is partly a style question, partly a correctness question. Submit the following sample (a strip-down of a class which deals with a block of data that contains an embedded header):
class Foo {
public:
Foo(size_t size)
: scratch_(new…
Dana M
- 198
- 1
- 11
3
votes
2 answers
Attempting to use vector's fill constructor in class member initialization fails. What is wrong?
When using std::vector's fill constructor (either form) with C++11's class member initialization feature, the following code fails to compile (under clang/llvm 3.6):
#include
class Foo
{
std::vector buf_(10); //compiler error!
…
U007D
- 5,772
- 2
- 38
- 44
3
votes
3 answers
Patterns for resetting objects to initial state
Suppose I have an object with a member that is expensive to construct, and the need for a reset() function that resets it to its initial state:
struct Example
{
// option 1: efficient, but need to duplicate initialization logic of reset()
…
anderas
- 5,744
- 30
- 49
3
votes
1 answer
D - Set default value for a struct member which is a multidimensional static array
I am using the D programming language.
I want to have a struct containing a multidimensional static array of ints initially filled with a non-zero value (in my case, zero is a valid entry, and I want to initially mark all entries as invalid).
As it…
Gassa
- 8,546
- 3
- 29
- 49
2
votes
3 answers
Complex statements in the member initialization part?
I have this:
struct myClass{
multiset > values ;
myClass(const char param1, const char param2) : values(less())
{ }
} ;
I need to initialize the values member with a different functor depending on the…
GetFree
- 40,278
- 18
- 77
- 104
2
votes
2 answers
Initialize a lambda function in the body of a class constructor
I can compile the following code without any problem (using gcc 11.1.0):
#include
template
class K {
Func f;
public:
K(Func _f): f{_f} {};
void do_thing(int x) {f(x);};
};
int main()
{
auto f = [](int x)…
MaPo
- 613
- 4
- 9
2
votes
1 answer
Why is object initialization different inside a struct?
I have created a class Point, here is the corresponding hpp file.
#ifndef POINT
#define POINT
class Point
{
protected:
int x;
int y;
public:
Point(int x = 10, int y = 10);
void movePoint(int moveX, int moveY);
void…
BaridunDuskhide
- 107
- 1
- 5
2
votes
1 answer
Initialising class members - default values or member-init-list?
I'm a bit confused about when and how to initialize members of a class in a constructor. If I understand things correctly, you can accomplish this by either including default values in the class definition, a constructor member initialiser list, or…
wds
- 61
- 1