Number at runtime

[ikl]

class A
{
....
};

For class A, several instances of it could be created, but their number is
unknown until runtime. How to do this?

Thanks!

 

[John Harrison]

class A
{
...
};

For class A, several instances of it could be created, but their number is
unknown until runtime. How to do this?

Use a vector.

#include <vector>

std::vector<A> vec(n); // creates n A objects

john

 

[ikl]

Use a vector.

#include <vector>

std::vector<A> vec(n); // creates n A objects

john

When I try it gives error: "error C2061: syntax error : identifier 'n'"
Does anyone know why? Thanks!

#include <vector>

using std::vector;

class B
{
};

int n = 1;

class A
{
vector<B> vec(n);

};

 

[Jon Willeke]

When I try it gives error: "error C2061: syntax error : identifier 'n'"
Does anyone know why? Thanks!

#include <vector>

using std::vector;

class B
{
};

int n = 1;

class A
{
vector<B> vec(n);

};

Member initialization is the constructor's responsibility:

class A
{
vector<B> vec;
public:
A() : vec( n ) {}
}

 

[Christopher Benson-Manica]

news:[email protected]...

When I try it gives error: "error C2061: syntax error : identifier 'n'"
Does anyone know why? Thanks!

vector<B> vec(n);

Yep - John wrote "n" to denote that you should replace it with a
number of your choice.

 

[ikl]

Member initialization is the constructor's responsibility:

class A
{
vector<B> vec;
public:
A() : vec( n ) {}
}

Why have to use constructor to initialize "vec"? Why not just like,

class B
{
int Number[10];
};

and don't need to initialize with "10"?

Thanks!