Statement a[637][i]++ increases the value of the cell 637/i of two-dimensional array a.
assert(0) simply aborts program execution at this point (since condition 0 means false, defining that the assertion is never met). Confer this
SO answer for a more detailed explanation.
solved In c++, what does an increment to a 2D array? Whats the function assert(0) doing? [closed]