--- bf.c	2012-09-28 17:57:12.000000000 +0900
+++ bf.c.patched	2019-02-04 23:59:48.874083499 +0900
@@ -139,16 +139,15 @@
 		register Progr *px = program + i;
 		if(px->op == '[')
 		{
-			int j, l=0;
+			int j, l=1;
 			for(j=i+1; j<psize; j++)
 			{
 				if((program+j)->op == '[')
 					l++;
 				if((program+j)->op == ']')
 				{
-					if (l)
-						l--;
-					else
+					l--;
+					if (!l)
 						break;
 				}
 			}
@@ -156,6 +155,11 @@
 				ErrorMsg(errBRACKET, "Unbalanced brackets.");
 			px->match = j;
 			(program+j)->match = i;
+		} else
+		if(px->op == ']')
+		{
+			if(px->match == -1)
+				ErrorMsg(errBRACKET, "Unbalanced brackets.");
 		}
 	}
 }
@@ -233,6 +237,10 @@
 				case '<':
 					x->step--;
 					break;
+				case ']':
+					x->op = *c;
+					x->match = -1;
+					break;
 				default:
 					x->op = *c;
 					break;