something wrong when i compile my own struct

[remlostime]

struct lineType
{
int x, y;
lineType(int tx, int ty)
{
if (tx == 0)
{
ty = 1 << 20;
tx = 1;
}
x = tx;
y = ty;
}
};
lineType line[30000];

when i compile it
error: no matching function for call to `lineType::lineType()
why?

 

[Lars Uffmann]

lineType(int tx, int ty)

when i compile it
error: no matching function for call to `lineType::lineType()
why?

You defined a "constructor" - your declaration would probably need to
look like
lineType line[30000](0, 0);

But I have never defined an array of classes, or an array of structs
that are defined like a class. So I wouldn't know for sure. Either way,
a workaround would be if you rename your inline function to something
other than the struct name.

Best Regards,

Lars

 

[Victor Bazarov]

lineType(int tx, int ty)

when i compile it
error: no matching function for call to `lineType::lineType()
why?

You defined a "constructor" - your declaration would probably need to
look like
lineType line[30000](0, 0);

That's a syntax error.

But I have never defined an array of classes, or an array of structs
that are defined like a class. So I wouldn't know for sure. Either
way, a workaround would be if you rename your inline function to
something other than the struct name.

.... or give the constructor the default arguments (if 0,0 are what
you want you could do

lineType(int tx = 0, int ty = 0);

) which should make it the default constructor, acceptable to use
with an array without specifying the initialisers for all elements.

V

 

[AnonMail2005]

struct lineType
{
  int x, y;
  lineType(int tx, int ty)
  {
    if (tx == 0)
    {
      ty = 1 << 20;
      tx = 1;
    }
    x = tx;
    y = ty;
  }};

lineType line[30000];

when i compile it
error: no matching function for call to `lineType::lineType()
why?

In order to create an array, your struct needs a default
constructor (i.e. one that takes no arguments).

HTH

 

[manish sahu]

struct lineType
{
  int x, y;
  lineType(int tx, int ty)
  {
    if (tx == 0)
    {
      ty = 1 << 20;
      tx = 1;
    }
    x = tx;
    y = ty;
  }};

lineType line[30000];

when i compile it
error: no matching function for call to `lineType::lineType()
why?

hey its a wrong method because u give a same name to structure and
compiler gets confused and we cannot have a constructor in c

 

[red floyd]

struct lineType
{
int x, y;
lineType(int tx, int ty)
{
if (tx == 0)
{
ty = 1 << 20;
tx = 1;
}
x = tx;
y = ty;
}};

lineType line[30000];

when i compile it
error: no matching function for call to `lineType::lineType()
why?

hey its a wrong method because u give a same name to structure and
compiler gets confused and we cannot have a constructor in c

So? It's C++. As has already been pointed out, the issue is that there
is no default constructor.

 

[Kira Yamato]

lineType(int tx, int ty)

when i compile it
error: no matching function for call to `lineType::lineType()
why?

You defined a "constructor" - your declaration would probably need to
look like
lineType line[30000](0, 0);

That's a syntax error.

But I have never defined an array of classes, or an array of structs
that are defined like a class. So I wouldn't know for sure. Either
way, a workaround would be if you rename your inline function to
something other than the struct name.

... or give the constructor the default arguments (if 0,0 are what
you want you could do

lineType(int tx = 0, int ty = 0);

) which should make it the default constructor, acceptable to use
with an array without specifying the initialisers for all elements.

Neat. I thought you need an actual default constructor, i.e., one that
takes no argument.

 

[Ron Natalie]

Neat. I thought you need an actual default constructor, i.e., one that
takes no argument.

Yep, the definition of a default constructor is not one with no args,
but one that can be called with no args. Similarly a copy constructor
is defined when you have the first arg of T& or const T& and any
additional args are defaulted.

 

[Kira Yamato]

Yep, the definition of a default constructor is not one with no args,
but one that can be called with no args. Similarly a copy constructor
is defined when you have the first arg of T& or const T& and any
additional args are defaulted.

Ooo. Double neat.