My First Objective-C

List.h:

#import <objc/Object.h>

@interface List : Object                          // List is a subclass of the superclass Object
{
    int list[100];                                // These are instance variables.
    int size;
}


/* Public methods */
- free;
- (int) addEntry: (int) num;
- print;

/* Private methods */
/* Other programs should not use these methods. */

- resetSize;

@end

List.m:

#import "List.h"

@implementation List

+ new                                           // factory method
{
    self = [super new];
    [self resetSize];
    return self;
}


- free
{
    return [super free];
}


- (int) addEntry: (int) num
{
    list[size++] = num;
    return size;
}


- print
{
    int i;

    printf("\n");
    for (i = 0; i < size; ++i)
        printf ("%i ", list[i]);
        puts("");
    return self;                                // Always return self
                                                                                                // if n
othing else makes sense.
}


- resetSize
{
    size = 0;
    return self;
}

Stack.h:

#import <objc/Object.h>

typedef struct StackLink {
        struct StackLink        *next;
        //void                  *data;
        int                     data;
} StackLink;


@interface Stack : Object
{
        StackLink *top;
    unsigned int size;
}

- free;
- push: (int) anInt;
- addEntry: (int) anInt;
- (int) pop;
- (unsigned int) size;

@end

Stack.m:

#import "Stack.h"
#import <stdlib.h>

@implementation Stack

#define NULL_LINK (StackLink *) 0

+ new
{
    self = [super new];
    top = NULL_LINK; //(StackLink *) 0;
    return self;
}


- free
{
    StackLink *next;

    while (top != NULL_LINK)
    {
        next = top->next;
        free ((char *) top);
        top = next;
    }
    return [super free];
}


- push: (int) value
{
    StackLink *newLink;

    newLink = (StackLink *) malloc (sizeof (StackLink));
    if (newLink == 0)
    {
        fprintf(stderr, "Out of memory\n");
        return nil;
    }
    newLink->data = value;
    newLink->next = top;
    top = newLink;
    size++;

    return self;
}


- addEntry: (int) value
{
        return [self push: value];
}

- (int) pop
{
    int value;
    StackLink *topLink;

    if (0 != size)
    {
        topLink = top;
        top = top->next;
        value = topLink->data;
        free (topLink);
        size--;
    }
    else
    {
        value = 0;
    }
    return value;
}


- (unsigned int) size
{
    return size;
}

- print
{
        StackLink *startLink;
        int i = size;

        startLink = top;

        while (startLink) {
                printf("Stack[%d] = %d\n", i, startLink->data);
                startLink = startLink->next;
                i--;
        }
        return self;
}

@end

main.m:

#import <objc/Object.h>
#import "List.h"
#import "Stack.h"

//int main(int argc, char *argv[])

void perform (id obj)
{
        [obj addEntry: 5];
        [obj print];
        [obj addEntry: 6];
        [obj addEntry: 3];
        [obj print];
}

main()
{
        id list;

        list = [List new];
        perform(list);
        [list free];

        id stack;
        stack = [Stack new];
        perform(stack);
        [stack free];
        printf("\n");
        return 0;
}

Makefile:

.SUFFIXES: .o .m

.m.o:
        $(CC) -c $(CFLAGS) $< -o $@

# Macros

CC=gcc

#CFLAGS=-Wall -Wno-import -mtune=core2 -mfpmath=sse -ffast-math -msse3 -fobjc-exceptions
CFLAGS=-Wno-import -mtune=core2 -g

LDFLAGS=-lobjc
SRCS=main.m List.m Stack.m
OBJS=$(SRCS:.m=.o)
EXECUTABLE=main

.PHONY: all

all: $(EXECUTABLE)

$(EXECUTABLE): $(OBJS)
        $(CC) $(LDFLAGS) -o $@ $(OBJS)

#$(OBJS): $(SRCS)
#       echo "$(CC) -c $(CFLAGS) $< -o $@"

clean:
        rm -f *.o $(EXECUTABLE)

TAGS: $(SRCS)
        ctags -R $(SRCS)