In c++, what does an increment to a 2D array? Whats the function assert(0) doing?

Question

I'm working on a code in C++ but i'm not sure what a[set][i]++; does. I was assuming that the value located in that array was incremented by 1, but i'm not sure.
Also, what's the function of assert(0); in the code? Thank for your help!

The code block is:

for (i=0; i<1S; i++)
{
   if (a[637][i] < a[637][15]) 
       {
          a[637][i]++;
          if (a[637][i] == 15)
             assert(0);
       }
    }
a[637][15] = 0;

Edit: Sorry i forgot to mention the background.
The definition of a is uint32_t a[2048][16];so 637 and i are values from a particular loop in order to compare them with another 2D array and then choose which line to evict. This is for a cache replacement policy but i just was curious for those cases. Thanks!

Assert is used to evaluate a equation and abort with or without a message if it fails. https://msdn.microsoft.com/en-us/library/9sb57dw4.aspx . — Nightforce2, Apr 26 '17 at 19:51
Can you show us definition of array a? assert is a c function stopping compilation if it's argument is false (i.e. 0), unless macro NDEBUG is defined. — Outshined, Apr 26 '17 at 19:51
`assert(0)` is the same as `assert(false)`, meaning that the program (in debug mode) will stop if it reaches that statement. So it means "this should never happen": — Bo Persson, Apr 26 '17 at 19:59
@Caribou No, it doesn't stop compilation. It aborts the program at runtime. — cdhowie, Apr 26 '17 at 19:59
Note also that you can rewrite that particular statement as `assert(a[637][i] != 15);`. — Bob__, Apr 26 '17 at 20:09
@cdhowie You're right, static_assert throws compile time error, my mistake. — Outshined, Apr 27 '17 at 08:59

score 0 · Accepted Answer · edited May 23 '17 at 12:26

0

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.

edited May 23 '17 at 12:26

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answered Apr 26 '17 at 20:00

Stephan Lechner

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In c++, what does an increment to a 2D array? Whats the function assert(0) doing?

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