Objective-C addObject seems to put object into all array indices - objective-c

Question

I am trying to learn how to make simple classes.
So far I am not getting the results expected using addObject and my class.
Here is what I have:
In my view controller:
#import "onoffclass.h"
In its viewDidLoad:
NSMutableArray *inTable;
onoffclass *therec;
onoffclass *readrec;
inTable = [NSMutableArray array];
therec = [[onoffclass alloc]init];
readrec = [[onoffclass alloc]init];
for (int lop=0;lop<3;lop++){
therec.parsedID = [NSString stringWithFormat:#"%i",lop];
[inTable addObject:therec];
NSLog(#"lop=%i onoff.parsedID=%#",lop,therec.parsedID);
for (int z=0;z<[inTable count];z++){
readrec = inTable[z];
NSLog(#" inTable[%i] parsedID=%#",z,readrec.parsedID);
}
}
In my onoffclass.h:
#interface onoffclass : NSObject
#property NSString *parsedID;
#property NSString *parsedOn;
#property NSString *parsedOff;
#property NSString *parsedAdj;
#property NSString *parsedRoom;
#property NSString *parsedBuilding;
#property NSString *parsedWho;
#property NSString *parsedInfo;
#property NSString *parsedBillable;
-(onoffclass*)initWithSomeString: (NSString*)blah AndSomeNum: (int)num;
-(NSString*)description;
#end
In my onoffclass.m:
#import <Foundation/Foundation.h>
#import "onoffclass.h"
#implementation onoffclass {
NSString *_parsedID;
NSString *_parsedOn;
NSString *_parsedOff;
NSString *_parsedAdj;
NSString *_parsedRoom;
NSString *_parsedBuilding;
NSString *_parsedWho;
NSString *_parsedInfo;
NSString *_parsedBillable;
}
-(onoffclass*)initWithSomeString: (NSString*)blah AndSomeNum: (int)num {
self = [super init];
_parsedID = blah;
_parsedOn = #"on";
_parsedOff = #"off";
_parsedAdj = #"adj";
_parsedRoom = #"room";
_parsedBuilding = #"building";
_parsedWho = #"who";
_parsedInfo = #"info";
_parsedBillable = #"billable";
return self;
}
-(NSString*)description {
return [NSString stringWithFormat: #"%#", _parsedID];
}
#end
Here is the output:
lop=0 onoff.parsedID=0
inTable[0] parsedID=0
lop=1 onoff.parsedID=1
inTable[0] parsedID=1
inTable[1] parsedID=1
lop=2 onoff.parsedID=2
inTable[0] parsedID=2
inTable[1] parsedID=2
inTable[2] parsedID=2
Why does it appears that addObject is updating all array indices and how do I fix this?
Thanks,
Dale

Answer 1

You are creating one instance of onoffclass (by the way class names should start with a capital letter) then you are adding the same instance again and again in the loop. Since classes are reference types changing a property affects all occurrences of the same instance.
Solution is to put the line to create an instance in the loop
for (int lop = 0; lop < 3; lop++) {
therec = [[onoffclass alloc] init];
...