Converting NSData to NSString in Objective c and How do I convert a NSString value to NSData?

NSData to NSString in ObjectiveC

NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"%@",str);

How do I convert a NSString value to NSData?

NSString* str = @"teststring";
NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding];