How to redefine an array in one statement?

Question

One of my apps that I'm working on at the moment relies on a multi-dimensional array. So far, I've been using a static array that was defined once, in a style similar to:

float exampleArray[2][2] = {{1, 2},
                            {3, 4}};

However, I'd now like to redefine this array, and such arrays cannot be easily redefined. Unlike when I initialised the array, I'd have to redefine every element of this array separately, for example:

exampleArray[1][1] = 3;
exampleArray[1][2] = 0.5;
exampleArray[2][1] = 17;
exampleArray[2][2] = 2;

Since I'm working on a 17x17 array, the idea of having to do this doesn't really appeal to me! (And I don't really want to keep each array in memory at once, so three arrays or a three-dimensional array isn't the right way to go about this)

I've looked into using a dynamic array instead. Theoretically, using a dynamic array, even I couldn't change everything in one go, I could free the memory for the old array, and then allocate memory for the new array.

However, I've not seen a way of defining a dynamic array in the style of the first example. Is there any easy way to define (or redefine) a dynamic array without directly manipulating one element at a time (i.e. in a similar fashion to my first example)?

EDIT: See the suggestions below for methods that doesn't require dynamic arrays. Thanks for the quick responses!

Define an other array and switch the pointers ?

matovitch
– matovitch

2013-11-17 15:08:48 +00:00
Commented Nov 17, 2013 at 15:08 — matovitch
– matovitch, Commented Nov 17, 2013 at 15:08
Use some for loops to get each element?

Mihai Maruseac
– Mihai Maruseac

2013-11-17 15:10:27 +00:00
Commented Nov 17, 2013 at 15:10 — Mihai Maruseac
– Mihai Maruseac, Commented Nov 17, 2013 at 15:10

godel9 · Accepted Answer · 2013-11-17 15:10:41Z

8

You can always copy one array to another using memcpy:

float exampleArray[2][2] = {{1, 2},
                            {3, 4}};

float newArray[2][2] = {{ 3, 0.5},
                        {17, 2}};

memcpy(exampleArray, newArray, sizeof(exampleArray);

answered Nov 17, 2013 at 15:10

godel9

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1 Comment

Ben Over a year ago

Great suggestion! Thanks for the incredibly fast responses!

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