If you want to do it as an IF statement:
If you want to do it more intelligently, do a switch:
BLOCKTYPE BlockType = GetBlock(a_BlockX, a_BlockY, a_BlockZ); if ((BlockType == E_BLOCK_WATER) || (BlockType == E_BLOCK_STATIONARY_WATER) || (BlockType == ...))
If you want to do it more intelligently, do a switch:
switch (GetBlock(a_BlockX, a_BlockY, a_BlockZ) { case E_BLOCK_STATIONARY_WATER: case E_BLOCK_WATER: { // TNT in these blocks doesn't do environmental damage break; } default: { // Destroy the neighboring blocks: for (int y = 0; y < ExplosionSizeInt; y++) ... } }