Question

I initialized an Array as

Double[][] myarr = Enumerable.Repeat(new double[12], 13).ToArray();

Then in a loop i am incrementing values like

myarr[0][0]++; 

This causes all values like myarr[1][0], myarr[2][0], myarr[3][0] ….. myarr[12][0] to increment by one.

This problem is not occurring when using a for loop (0-12) i am initializing like

myarr[i] = new double[12];

Why is this so?

Answer 1

Other answers have explained the problem. The solution is to create a new array on each iteration, e.g.

double[][] myarr = Enumerable.Range(0, 13)
                             .Select(ignored => new double[12])
                             .ToArray();