Trouble with Method and Return Value Calculation - ios

Question

I created a method to calculate a simple calculation.
I want the method to return an int and take 2 int parameters.
I created a class called calculation. I imported calculation into the viewController.m and created an action 2 textFields and a text Label. I am using this view for testing the method.
My method return 0 in the calculation. What am I doing wrong? It's so simple but I can't seem to figure out where I'm making my mistake. Here is the code.
Calculation.h
#import <Foundation/Foundation.h>
#interface Calculation : NSObject
#property (nonatomic) int odometerStart;
#property (nonatomic) int odometerEnd;
#property (nonatomic) int odometerTotal;
- (int)mileageStart:(int)start mileageEnd: (int)end;
#end
Calculation.m
#import "Calculation.h"
#implementation Calculation
#synthesize odometerEnd, odometerStart, odometerTotal;
- (int)mileageStart:(int)start mileageEnd:(int)end
{
odometerStart = start;
odometerEnd = end;
odometerTotal = end - start;
return odometerTotal;
}
#end
viewController.h
#import <UIKit/UIKit.h>
#interface MileageViewController : UIViewController
- (IBAction)calculateMileage:(id)sender;
#property (strong, nonatomic) IBOutlet UITextField *startLabel;
#property (strong, nonatomic) IBOutlet UITextField *endLabel;
#property (strong, nonatomic) IBOutlet UILabel *displayLabel;
#end
viewController.m
#import "MileageViewController.h"
#import "Calculation.h"
#implementation MileageViewController
#synthesize startLabel;
#synthesize endLabel;
#synthesize displayLabel;
- (void)viewDidUnload
{
[self setStartLabel:nil];
[self setEndLabel:nil];
[self setDisplayLabel:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (IBAction)calculateMileage:(id)sender {
Calculation *mileage = [[Calculation alloc] init];
int odomStart = [[startLabel text] intValue];
int odomEnd = [[endLabel text ] intValue];
[mileage mileageStart:odomStart mileageEnd:odomEnd];
mileage.odometerTotal = displayLabel.text.intValue;
NSLog(#"THe total is %d", mileage.odometerTotal);
My total keeps equaling 0. The calculation isn't being calculated.

Answer 1

Your statement is backwards. You're trying to set the value of odometerTotal to the value of your label, but you want it the other way around. It should be:
displayLabel.text = [NSString stringWithFormat:#"%d",mileage.odometerTotal];
However, mileage returns an int value, so you don't really need the odometerTotal property in your Calculation class . You could do it like this:
displayLabel.text = [NSString stringWithFormat:#"%d",[mileage mileageStart:odomStart mileageEnd:odomEnd]];

Answer 2

I saw the whole program, and the assignment you did seemed wrong,
the bold pointed was as below:
mileage.odometerTotal = displayLabel.text.intValue;
you want to use the calculate class to calculate the total value. while the order should be opposite.
How about this:
displayLabel.text.iniValue = mileage.odometerTotal;
then use the NSLog method to print your expected result.