MQL4 Arrays

[Tbone]

Are MQL4 arrays sparse?

For example, if I define an array:

double a1[][4];

Then add some entries at arbitrary points:

a1[1234][0] = 3.14;

Does the array implemention add entries 0 to 1233 for the first dimension?

The purpose of this would be to track order specific information on a per ticket basis.

[Tbone]

I guess another question which is related to the same topic, how would I iterate a sparse array (assuming the arrays are sparse)

[Ray]

Never seen it mentioned, I assume, no.