Can't initialise an array

Question

Okay, I'm pretty new when it comes to C++ (having moved over from VB) and I can't seem to work out how to populate an array without doing:

array[0] = 1
array[1] = 2

etc etc

So as could be expected, I have tried this:

float posVector[3]; //Declared outside of int main() as needs to be global
posVector = {0.0f,0.0f,0.0f}; //Inside int main()

Which is causing this error to be displayed:

extended initializer lists only available with -std=c++0x or -std=gnu++0x [enabled by default]

Nothing I have been able to locate online so far has been of any help. So any advice you can give me on fixing this will be appreciated!

God knows, it's whichever one is used in the online Zero Robotics Tournament IDE at zerorobotics.mit.edu — ScottishTapWater
– ScottishTapWater, Commented Sep 29, 2015 at 20:57

HelloWorld · Accepted Answer · 2015-09-29 21:18:59Z

5

Once the array is declared it cannot be initialized using the initializer list. You can go with

float posVector[] = {0.0f,0.0f,0.0f};

or even better go with std::vector:

#include <vector>

std::vector<float> posVector = {0.0f,0.0f,0.0f};

edited Sep 29, 2015 at 21:18

answered Sep 29, 2015 at 20:57

HelloWorld

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8 Comments

ScottishTapWater Over a year ago

Right okay, so how do I make it globally available if it needs to be populated at run time? Can you please elaborate on std::vector?

HelloWorld Over a year ago

The vector can be placed outside a function. What exactly are you looking for?

ScottishTapWater Over a year ago

I'm trying to create an array which will be globally available and hold the current x,y,z values for the position of a sattelite

HelloWorld Over a year ago

Try to avoid global variables. When a lot of functions are involved it's hard to remember which function should write or just read from/to the array. When threading comes into the game it becomes even more horrible. Consider to abstract and encapsulate your data. You use C++, so use what it offers you.

ScottishTapWater Over a year ago

Okay... Sounds scary, but I'll do some research and give it a shot, I know scope should be limited as far as possible.

|

Aram Antonyan · Accepted Answer · 2015-09-29 20:56:34Z

1

It can be done like this:

float f[] = {1.0, 2.0, 3.0, 4.0, 5.0};

answered Sep 29, 2015 at 20:56

Aram Antonyan

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Comments

user5378236 · Accepted Answer · 2015-09-29 20:59:04Z

0

Shortest way i think: float posVector[] { 0.0f,0.0f,0.0f };

answered Sep 29, 2015 at 20:59

user5378236

Comments

SergeyA · Accepted Answer · 2015-09-29 21:18:32Z

0

As far as I understand, the question is not about INITIALIZING the array, but about assigning the array after it was already created. The answer is 'no way'. Arrays can not be assigned after they are initialized. However, arrays of fixed sizes some time might be more adequately presented as structs, and this is exactly the case! Coordinates are much better presented as structs!

Not commenting on the neccessity of global variable (most likely, not needed) here is the way to make it work:

struct Coordinate {
    float x;
    float y;
    float z;
};

Coordinate coord;

void foo() {
    coord = {1, 2, 3};
}

answered Sep 29, 2015 at 21:18

SergeyA

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