Basic Problem reading input from NSTextCell in Xcode

Hi, I'm new to Objective C and just doing some basics.

All I want to do is;

- read a value from one text field
- double it
- output it to another text field

But I'm stuck on the first, each time I try to read the value in it returns a value of 0 even though the entry is clearly 1 or 3 or 100.

This is the snippet

input=[inputfield floatValue];

Where inputfield is the NSTextCell box and input is a float.

The rest of the code is below in case it is useful.

Please help, going insane!

readwrite.m
*******************************************************

#import "readandwrite.h"

@implementation readandwrite

@synthesize input, output;

-(IBAction)calculate: (id) sender
{

// float input;

input=[inputfield floatValue];
self.output=input*2.0;
printf("Input is %f\n",input);
printf("Output is %f\n",output);
[outputfield setFloatValueutput];
}

@end

readandwrite.h
*******************************************************

#import <Cocoa/Cocoa.h>


@interface readandwrite : NSObject {
char input;
float output;
IBOutlet NSTextField *outputfield;
IBOutlet NSTextField *inputfield;


}

@property(readwrite) float output;
@property(readwrite) char input;


-(IBAction)calculateid)sender;

@end