two dim array for loops

[Hit]

hello all. i'm having trouble trying to think of a 'formula' or 'equation', etc

its a simple 8 x 8 (64) 2 dimensional array

im printing the board through two for loops, I'm trying to emulate how a bishop can move (diagonally). I got the one working, but i cant think of a way to get the other side to work:

#include <iostream>
using namespace std;

enum
{
	rows = 8,	//across
	cols = 8	//vertical
};

struct sboard
{
	int arr[rows][cols];
};

void printb(sboard const *board)
{
	for(int i=0;i<rows;i++)
	{
		int offj = 7;
		for(int j=0;j<cols;j++)
		{
			if(i == j || (i == 0 && offj == 0))
			{
				cout << "X";
			}
			//cant modulus/divide by zero
			else if(offj !=0 && (i % offj == 0 && i / offj == 1))
			{
					cout << "X";
			}
			else
			{
				cout << board->arr[i][j];
			}
			offj-=1;
		}
		cout << endl;
	}
}

int main()
{
	sboard board;

	for(int i=0;i<rows;i++)
	{
		for(int j=0;j<cols;j++)
		{
			board.arr[i][j] = i;
		}
	}

	printb(&board);

	cin.get();cin.get();
	return 0;
}

note that i want to be able to do this without making another for loop or function. it should fit in the else if statement. yes i feel kinda dumb

[Lowest0ne]

I guess cols - j ?

[Hit]

found it out.. took me a while. at least i practiced my modulus

for(int i=0;i<rows;i++)
	{
		int offj = 7;
		for(int j=0;j<cols;j++)
		{
			if(i == j || (i == 0 && offj == 0))
			{
				cout << "X";
			}
			//cant modulus/divide by zero
			else if(offj !=0 && (i % offj == 0 && i / offj == 1))
			{
					cout << "X";
			}
			else
			{
				cout << board->arr[i][j];
			}
			offj-=1;
		}
		cout << endl;
	}