push_back(class)

[en liten kille]

I've got a class containing 3 floats.

class a{
float x,y,z;
};

And I created a vector with that type.

vector<a> b;

How do I use the push_back funtion to give b 0,0,0?

i tried this:
b.push_back(0,0,0);

It didn't work...

[Cubbi]

First, your class needs a three-argument constructor:

class a {
    float x,y,z;
 public:
    a(float a, float b, float c) : x(a), y(b), z(c) {}
};

then you can use either

b.emplace_back(0, 0, 0);
or

b.push_back(a(0, 0, 0));

online demo: http://ideone.com/5Ngbx

[Athar]

When making x, y, z public (as they should be), you can write the following, even without creating a constructor:
b.push_back({0,0,0});

[en liten kille]

It's not working. I wrote:

b.push_back({0,0,0});

But some primary-expression is expected before "{" token.

[Athar]

This type of initialization and emplace_back are part of C++11. You need a recent compiler and you need to add the compiler switch -std=c++0x (GCC, ICC, clang).

[Peter87]

What Cubbi said about constructor and push_back should work even if you have an older compiler.

[en liten kille]

Is it necessary that the floats are private then?

[Athar]

No, it doesn't matter (to the compiler, that is).

[en liten kille]

This is weird. It's not working but thank you anyway. Guess I'll have to solve the problem in some other way.

[Athar]

Or you could just describe your problem in a more informative way than "it doesn't work" (without any information of what "it" even is).

[chipp]

did you do like what cubbi said?

[en liten kille]

yes