마방진(magic square)

public class ExerciseCh2_8 {
	public static void main(String[] args) throws java.io.IOException{
		int n = System.in.read() - '0';
		int [][] matrix = new int [n][n];
		int number, row, col, row_b, col_b;
		
		for(row=0; row<n; row++)
			for(col=0; col<n;col++)
				matrix[row][col] = 0;
		
		// 값 초기화
		row = 0;
		col = n/2;
		number = 1;
		matrix[row][col] = number; //[0][1]에 1넣음, [0][2]에 1넣음
		
		while(number<=n*n) {
			matrix[row][col] = number;
			
			row_b = row;
			col_b = col;
			col++;
			row--;
			
			if(row < 0) //row가 -1
				row = row % n + n;
			if(col > n-1) //col이 n
				col = col % n;
			if(matrix[row][col]!=0) //이미 숫자가 있으면 밑에다 적음
			{
				row = row_b+1;
				col = col_b;
			}
			number++;
		}
		for(row=0; row<n; row++)
		{
			for(col=0; col<n;col++)
				System.out.print(matrix[row][col]);
			System.out.println();
		}
	}

}