How can I initialize 2nd array elements which are 'double data type' as -1 or 0 easily

Question

I want to initialize double 2nd array elements as -1 or 0 easily.

In case of integer, we can write like below

int cache[100][100];
memset(cache, -1, 100*100*sizeof(int));

But In case of double, How can I initialize this 2nd array easily? the best approach that I can handle, but quite ugly, is below

double cache[100][100];
for(int i=0; i<100; i++)
   for(int j=0; j<100; j++)
       cache[i][j] = -1;

Does anybody know best solution about this?

Are you sure the integer version does what you expect? `memset` fills a memory area with a consistent byte, not an int. Version 2 is a much clearer indication of what you actually want to achieve. — John3136, Jul 15 '16 at 06:01
I know what you mean. Therefore, 'memset' can fill a memory area -1 or 0. What I want to know is that there is a certain STL that can achieve above goal. — Daniel kim, Jul 15 '16 at 06:12
@LưuVĩnhPhúc not sure it is a duplicate as that answer doesn't really address 2D arrays (or if it does I didn't look hard enough ;-) — John3136, Jul 15 '16 at 06:21

score 0 · Accepted Answer · answered Jul 15 '16 at 06:27

0

Initializing elements of an array to 0 is simple.

double cache[100][100] = {};

Initializing them to -1 is not easy. You'll have to have the entire array written out as:

double cache[100][100] = {-1, repeat 10000 times};

You can set them to -1 using:

std::fill(cache[0], cache[0]+100*100, -1);

answered Jul 15 '16 at 06:27

R Sahu

1 Answers1