XCODE reading text from file erases variables - xcode

Question

This my be the strangest error I've ever seen.
I'm creating a maze game that loads levels from text files, but if the file has more than three rows, it seems to randomly change most of my variables. I load in a text file then run through the lines and create an object at the proper location based on its letter.
Any advice?
Text File:
TTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTT
TTTTTRPPGPPDTTTTT
TTTTTPTPTPTPTTTTT
TTTTTPPPWPPPTTTTT
TTTTTPTPPPTPTTTTT
TTTTTPPPTPPPTTTTT
TTTTTPTPPPTPTTTTT
TTTTTUPPPPPLTTTTT
TTTTTTTTPTTTTTTTT
TTTTTTTTBTTTTTTTT
TTTTTTTTPTTTTTTTT
NSString *path = [[NSBundle mainBundle] pathForResource:#"map2c" ofType:#"txt"];
NSString *contents = [NSString stringWithContentsOfFile:path encoding:NSASCIIStringEncoding error:nil];
NSArray *lines = [contents componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:#"\r\n"]];
int y = 0;
for (NSString* line in lines) {
NSString* ty = #"TBGWUDLRP";
char *str = (char *)[line UTF8String];
char *str2 = (char*)[ty UTF8String];
grannyMoving = 2;
int x = str2[0];
char x2 = str2[1];
char GrannyStr = str2[2];
char wolfStr = str2[3];
char UpStr = str2[4];
char DownStr = str2[5];
char leftStr = str2[6];
char rightStr = str2[7];
char PathStr = str2[8];
y--;
maxY = y;
if (line.length) {
maxI = line.length;
for (int i = 0; i< line.length; i++) {
SKSpriteNode* tree = [SKSpriteNode spriteNodeWithImageNamed:#"tree3"];
tree.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(31, 31)];
tree.physicsBody.affectedByGravity = false;
tree.physicsBody.dynamic = NO;
tree.position = CGPointMake(64*i+20, 64*y+800);
tree.zPosition = -1* tree.position.y;

Answer 1

From the documentation:
This C string is a pointer to a structure inside the string object,
which may have a lifetime shorter than the string object and will
certainly not have a longer lifetime. Therefore, you should copy the C
string if it needs to be stored outside of the memory context in which
you use this property.
To fix this you have to make a copy of the characters returned by UTF8String. This answer provides two solutions.