c++ - Placing of pillars

Question

I am trying to place pillars on a board that alternate between these amount of pillars (I don't think I explained properly), but for example on row 1 it will have 9 pillars and row 2 it will have 8 pillars. I wanted to try do it in a nested for loop but not really sure how to go about the code within the blocks.

At the moment I have this: here are my variables:

float PegPosX = -1.0f;
float PegYStartPos;
float PegPosY = 6.0f;
int Pegs = 0;
int PegsInRow = 8;

while(Pegs < NumPegs){
     for (int row = 0; row < PegsInRow; ++row) { 
     int num_cols = (row % 2 == 0) ? 9 : 8;
     PegPosY -= 0.5f;
         for (int col = 0; col < num_cols; ++col){ 
             PegPosX += 1.0f; 
            displayPegs[Pegs].PegPosition(PegPosX, PegPosY);
         }
    }
    ++Pegs;
}

Answer 1

for (int row = 0; row < num_rows; ++row) {
   int num_cols = (row % 2 == 0) ? 9 : 8;
   for (int col = 0; col < num_cols; ++col) {
       placePillar(...);
   }
}