From 3e1432e89f97c566b03fadefab8be97e04eed20f Mon Sep 17 00:00:00 2001
From: Jinwei Zhao <clarkzjw@gmail.com>
Date: Mon, 23 Feb 2015 15:13:30 +0800
Subject: fix loop

---
 brainfuck.c | 53 ++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 40 insertions(+), 13 deletions(-)

diff --git a/brainfuck.c b/brainfuck.c
index ceb52c4..5cd021e 100644
--- a/brainfuck.c
+++ b/brainfuck.c
@@ -8,6 +8,7 @@ typedef struct brainfuck{
 	char command[MAX_DATA];
 	char *ptr;
 	int count;
+	int num;
 }bf;
 
 bf one;
@@ -17,6 +18,7 @@ void init()
 	char c;
 	memset(&one, 0, sizeof(one));
 	one.count = 0;
+	one.num = 0;
 	one.ptr = one.data;
 
 	while ((c = getchar()) != EOF)
@@ -25,7 +27,7 @@ void init()
 			break;
 		one.command[++one.count] = c;
 	}
-	one.command[0] = one.count;
+	one.num = one.count;
 	one.command[one.count] = '\0';
 }
 
@@ -33,6 +35,8 @@ void run()
 {
 	char c;
 	int i;
+	int left;
+	int right;
 
 	one.count = 0;
 	while (c = one.command[++one.count])
@@ -40,16 +44,22 @@ void run()
 		switch (c)
 		{
 		case '+':
-			(*one.ptr)++;
+			if (*one.ptr == 255)
+				*one.ptr = 0;
+			else
+				++*one.ptr;
 			break;
 		case '-':
-			(*one.ptr)--;
+			if (*one.ptr == 0)
+				*one.ptr = 255;
+			else
+				--*one.ptr;
 			break;
 		case '>':
-			one.ptr++;
+			++one.ptr;
 			break;
 		case '<':
-			one.ptr--;
+			--one.ptr;
 			break;
 		case ',':
 			*one.ptr = getchar();
@@ -58,31 +68,48 @@ void run()
 			putchar(*one.ptr);
 			break;
 		case '[':
+			left = 0;
 			if (*one.ptr != 0)
 				break;
 			else
 			{
-				for (i = one.count + 1; i <= one.command[0]; i++)
+				for (i = one.count + 1; i <= one.num; i++)
 				{
-					if (one.command[i] == ']')
+					if (one.command[i] == '[')
+						++left;
+					else if (one.command[i] == ']')
 					{
-						one.count = i;
-						break;
+						if (left == 0)
+						{
+							one.count = i;
+							break;
+						}
+						else
+							--left;
 					}
+					
 				}
 			}
 			break;
 		case ']':
+			right = 0;
 			if (*one.ptr == 0)
 				break;
 			else
 			{
 				for (i = one.count - 1; i >= 1; i--)
 				{
-					if (one.command[i] == '[')
+					if (one.command[i] == ']')
+						++right;
+					else if (one.command[i] == '[')
 					{
-						one.count = i;
-						break;
+						if (right == 0)
+						{
+							one.count = i;
+							break;
+						}
+						else
+							--right;
 					}
 				}
 			}
@@ -97,4 +124,4 @@ int main(int argc, char **argv)
 	init();
 	run();
 	return 0;
-}
\ No newline at end of file
+}
-- 
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