Solution to Exercise 4 Chapter 11..!

[danish]

//  CalculatorTrig.h

Code: (Objective-C)

#import "Calculator.h"
#import <Math.h>

@interface Calculator (CalculatorTrig)

- (double) sin;
- (double) cos;
- (double) tan;

@end

//  CalculatorTrig.m

Code: (Objective-C)

#import "CalculatorTrig.h"

@implementation Calculator (CalculatorTrig)

- (double)sin
{   
    d = sin(number);
    
    return d;
}

- (double)cos
{
    d = cos(number);
    
    return d;
}

- (double)tan
{
    d = tan(number);
    
    return d;
}

@end

//  Calculator.h

Code: (Objective-C)

#import <Foundation/Foundation.h>

@interface Calculator : NSObject
{
    double number;
    double d;
}

@property double number, d;

- (void) print;


@end

//  Calculator.m

Code: (Objective-C)

#import "Calculator.h"

@implementation Calculator

@synthesize number, d;

- (void)print
{
    printf("%.2f\n", d);
}

@end

//  main.m

Code: (Objective-C)

#import "CalculatorTrig.h"

int main (int argc, const char * argv[])
{

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
    
    Calculator *myCalc = [[Calculator alloc] init];

    [myCalc setNumber:4];
    
    [myCalc tan];
    [myCalc print];
    
    [myCalc sin];
    [myCalc print];
    
    [myCalc cos];
    [myCalc print];
    
    [myCalc release];
    [pool drain];
    return 0;
}

cheers... 

[danish]

You dont have to import the math.h in the category header file..my bad..math.h gets imported automatically when you import Foundation.h

cheers..