question about default constructor

[July]

consider the following code:
class A {
public:
A(int i) : i(i) {
}

private:
int i;
};
int main()
{
A a;

return 0;
}

The code cannot compile because there is no default constructor of
class A, but the book says that "the compiler will generate the default
constructor if you don't define it"

What's wrong ?

 

[Jim Langston]

consider the following code:
class A {
public:
A(int i) : i(i) {
}

private:
int i;
};
int main()
{
A a;

return 0;
}

The code cannot compile because there is no default constructor of
class A, but the book says that "the compiler will generate the default
constructor if you don't define it"

What's wrong ?

I beleive it's actually, "the compiler will generate a defautl constructor
if you don't define any constructor".

 

[Alf P. Steinbach]

* July:

the book says that "the compiler will generate the default
constructor if you don't define it"

Which book is that (so that others can avoid it)?

 

[benben]

consider the following code:

class A {
public:
A(int i) : i(i) {
}

private:
int i;
};
int main()
{
A a;

return 0;
}

The code cannot compile because there is no default constructor of
class A, but the book says that "the compiler will generate the default
constructor if you don't define it"

What's wrong ?

The standard goes "If there is no user-defined constructor for class X, a
default constructor is implicitly declared."

Well, you declared (and defined) a constructor indeed, so the compiler won't
synthesize the default constructor for you. Not that the quote above didn't
say "if there is no user-defined DEFAULT constructor...".

Regards,
Ben

 

[Jaspreet]

consider the following code:
class A {
public:
A(int i) : i(i) {
}

private:
int i;
};
int main()
{
A a;

return 0;
}

The code cannot compile because there is no default constructor of
class A, but the book says that "the compiler will generate the default
constructor if you don't define it"

What's wrong ?

In this case you will **not** have a default constructor generated by
the compiler since you have defined your own paramterised constructor.

Probably the next sentence/chapter in the book would have been that
"the compiler generates a default constructor if and only if you do not
have any constructor declared/defined in your class".