int[][] tab = {
	            {1, 0, 0,},
	            {0, 1, 0,0},
	            {0, 0, 1}
	        };
	        boolean Diagonal = true;
	        boolean rectangular = true;
	        while (rectangular==true){
	        for (int i = 0; i < tab.length; i++) {
	        	if(tab.length != tab[i].length){
	        		System.out.println("error");
	        		rectangular = false;
	        	}
	        	
	        	for (int j = 0; j < tab[i].length; j++) {
	                System.out.print(tab[i][j] + " ");
	                if (j!= i && tab[i][j] != 0) {
	                    Diagonal = false;
	                }
	                
	            }
	            
	            System.out.println("");
	        }
	        
	        }
	        
	        if (Diagonal) {
	            System.out.println("okay");
	        } 
	        //else if(rectangular == false){ System.out.println("not square :( ");} 
	        else {
	            System.out.println("not okay :( ");
	        }