Arrays can be multidimensional and to add another dimension you add another set of square brackets:
int two[2]; int four_by_three[4][3];
The first example creates an array of two integers, the second creates a two-dimensional array with 12 integers arranged so that there are four rows of three columns. Of course, row and column are arbitrary and treat the two-dimensional array like a conventional spreadsheet table, but it helps to visualize how the data is arranged in memory.
Note that there are square brackets around every dimension. C++ is different to other languages in this respect, so a declaration of int x[10,10] will be reported as an error by the C++ compiler.
Initializing multidimensional arrays involves ...