CODEWITHSUNDEEP
c++if-statementwhile-loop
Raymond Gilbert
Raymond Gilbert

Reputation: 5

if-statement executing when it shouldn't (kind of)

int trees = 3;
int tree_x, tree_y;
for(int r = 0; r < m_townsize; r++)
{
  for(int c = 0; c < m_townsize; c++)
  {
    if(r == 0 || c == 0 || r == (m_townsize - 1) || c == (m_townsize - 1))
      m_town[r][c] = 'W';
    while(trees > 0)
    {
      tree_x = random() % m_townsize;
      tree_y = random() % m_townsize;
      cout << tree_y << "," << tree_x << endl;
      if(m_town[tree_y][tree_x] == ' ')
      {
        m_town[tree_y][tree_x] = 'T';
        trees -= 1;
      }
    }
  }
}

According the code I have written, if there is a space character at the coordinate of the tree, it should place a tree and lower the tree count by 1.

If there is not a space there, it should skip placing a tree, thus not decrementing. This should cause it to pick another set of coordinates and run through again.

However, if you look at this particular output it is running to the if-statement skipping the first option to replace it with a T--since it is a W--but still decrementing by 1. I don't get it. It should skip the statement all together, not skip just the first line. Netbeans tells me my brackets are right, so it shouldn't be an issue with the assignment belonging to the if and the decrement belonging to the while.

If I make a do-while loop it places a whole bunch. I don't know what's happening.

enter image description here

This output placed 2 trees.

Upvotes: 0

Views: 191

Answers (1)

Yakk - Adam Nevraumont
Yakk - Adam Nevraumont

Reputation: 275230

You are walking over each coordinate.

If it is on the edge you put a 'W'. Then you randomly place a tree 'T'.

Then you proceed to the next coordinate.

This means you can place some trees in squares before you overwrite with a 'W'.

Finish all the walls before placing trees. Consider a more efficient way to place walls to, like doing each edge instead of loopimg over the middle abd doing nothing.

Upvotes: 1

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