Can anyone please tell me how to write NSMutableArray of custom class objects to file? below is the code which i am using to write my array "medicationsArray" to file. medicationsArray contains the objects of below medicationData class

@interface medicationData: NSObject { NSString *drName; NSString *date; NSString *description; } @end

NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *documentDir = [path objectAtIndex:0];
NSString *pathWithFileName;

NSString *pathWithFileName = [NSString stringWithFormat:@"%@/medicationsArray",documentDir];
[medicationsArray writeToFile:pathWithFileName atomically:NO];

by using this code i am not able to create a file. can anyone help me in this, thanks in advance