Programs 9.4 and 9.5

[plantboy]

Hello,

Here is my code for program 9.4, copied from the book:

Code: (Objective-C)

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

    @autoreleasepool {
       
        Fraction *f = [[Fraction alloc] init];
        [f noSuchMethod];
        NSLog(@"Execution continues!");

    }
    return 0;
}

I am unfortunately not able to re-create the error, because XCode will not run the job. Please see the attached screenshot. (The entire point to this exercise is to submit the job and to see the error during runtime.)

I have a similar problem with program 9.5.

Thanks!

[plantboy]

I think I found the answer over here:
http://classroomm.com/objective-c/index.php?action=printpage;topic=6265.0

[kritchens]

yea it didnt work for me either, you can however see this in action if you do the following :

add the Fraction.h and Complex.h files,

Set them to the ID dataValue Variable

and while dataValue is now actually a Complex Object attempt to call the SetTo:SetOver: Method for fraction and you will get the error. This teaches a couple things such as how careful you have to be when using the ID variable type and how the Exceptions work. Try it out!

Code: (Objective-C)

#import <Foundation/Foundation.h>
#import "Fraction.h"
#include "Complex.h"
    
    int main(int argc, const char * argv[])
    {
        
        @autoreleasepool {
            
            id dataValue;
            Fraction *f1 = [[Fraction alloc]init];
            Complex  *c1 = [[Complex alloc]init];
            
            
            [f1 setTo:2 over:5];
            [c1 setReal:10.32 setImaginary:2.5];
            
            dataValue = f1;
            dataValue = c1;
            @try {
                [dataValue setTo:5 over:6];
            }
            @catch (NSException *exception) {
                NSLog(@"Caught %@%@",[exception name],[exception reason]);
            }
            NSLog(@"Execution Continues");
            
            
            
            
            
        }
        return 0;
    }