How can I create array of numbers in Objective-C? - objective-c

Question

i trying to create my firsy iphone program and i realize that making an array or matrix of 2 dims is difficult for me... :-(
*how and where i declarer somthing like this (take from java) so all the function can see it:
int[] myArray = new int[6];
*how can i trnslete this function:
public int[] sortArray (int[] myArray){
int tmp;
for (int x = 0; x < myArray.length; x++) {
for (int y = x+1; y < 6; y++) {
if (myArray[y] < myArray[x]) {
tmp = myArray[x];
myArray[x] = myArray[y];
myArray[y] = tmp;
}
}
}
return myArray;
}
*and how i call this function?
sortArray(myArray);
thanks for everyone!!!
sharon

Answer 1

You can do it with one line of code:
NSArray *array = #[#[#1, #2, #3],
#[#4, #5, #6],
#[#7, #8, #9]];
Learn about Objective-C literals here.

Answer 2

As in C,
int twoDArray[3][3];
In objective-C
NSArray *a=#[#"apple",#"axe",#"ant"];
NSArray *b=#[#"ball",#"book",#"baby"];
NSArray *c=#[#"cup",#"cat",#"cow"];
NSArray *twoDArray=#[a,b,c];
or in one statement:
NSArray *twoDArray=#[#[#"apple",#"axe",#"ant"],
#[#"ball",#"book",#"baby"],
#[#"cup",#"cat",#"cow"]];
EDIT:
NO need to convert that java function to obj-c method.
To sort the array :
NSArray *sortedArray = [array sortedArrayUsingComparator:^(id str1, id str2) {
return [((NSString *)str1) compare:((NSString *)str2) options:NSNumericSearch];
}];
EDIT 2: (Removed unwanted typecast of nsstring to id and back to string)
NSArray *sortedArray = [array sortedArrayUsingComparator:^(NSString *str1, NSString *str2) {
return [str1 compare:str2 options:NSNumericSearch];
}];

Answer 3

Declare in your respective .h file
NSMutableArray *numbers;
Then in your .m file
numbers = [[NSMutableArray alloc] init];
for (NSInteger i = 0; i < 6; i++)
[numbers addObject:[NSNumber numberWithInteger:i]];
and declare it in your .h as
-(NSMutableArray *)sortArray:(NSMutableArray *)numbers;
This is the translated method above in Objective-C:
-(NSMutableArray *)sortArray:(NSMutableArray *)numbers
{
NSInteger tmp = 0;
for(int x = 0; x < [numbers count]; x++)
for(int y = x + 1; y < 6; y++)
if([numbers objectAtIndex:y] < [numbers objectAtIndex:x])
{
tmp = [numbers objectAtIndex:x];
[numbers replaceObjectAtIndex:x withObject:[numbers objectAtIndex:y]];
[numbers replaceObjectAtIndex:y withObject:tmp];
}
return numbers;
}
Also you can call a method in objective-c as follows:
[self sortArray:numbers];

Answer 4

You seem to have (at least) two related-but separate questions here.
1/ how to create an array of numbers
Objective-C arrays come as immutable NSArrays (fixed contents) or mutable NSMutableArrays (you can add delete and shuffle contents around). You sort function as written is asking for a mutable array.
To create and populate an immutable array with NSNumber objects:
NSArray* array = #[#3,#5,#8,#2,#9,#1]; //"#1" is an NSNumber object literal
//access: array[3] etc
Multidimensional:
NSArray* arrayOfArrays #[#[#3,#5,#8],#[#2,#9,#1]];
//access: arrayOfArrays[1][2] etc
To create an empty variable-length mutable array
NSMutableArray* mutableArray = [[NSMutableArray alloc] init];
Create and populate a variable-length mutable array
myArray = [NSMutableArray arrayWithObjects:#3,#5,#8,#2,#9,#1, nil]; //note nil termination
To turn your immutable NSArray into a mutable NSMutableArray
NSMutableArray* mutableArray = [array mutableCopy];
(but take care, this will only render the top level as mutable, if it contains immutable subarrays they will remain immutable)
Objective-C collections (NSArray, NSDictionary, NSSet) can only hold objective-C objects. Therefore if you want to store ints or floats you need to box them into objective-C NSNumber objects before adding to a collection, and unbox them again to access the value.
int x;
float y;
NSNumber xNum = [NSNumber numberWithInt:x]; //box
NSNumber yNum = [NSNumber numberWithFloat:y]; //box
x = [xNum intValue]; //unbox
y = [yNum floatValue]; //unbox
2/ how to translate code
Here is a like-for-like translation:
To create the (mutable) myArray object:
NSMutableArray* myArray = [[NSMutableArray alloc] init];
Populate it:
[myArray addObjects:#3,#6,#8,#1,#9,nil]; //last value is nil to indicate termination
The method:
- sortArray:(NSMutableArray*)myArray
{
id tmp;
for (int x = 0; x < [myArray count]; x++) {
for (int y = x+1; y < 6; y++) {
if ([myArray[y] floatValue] < [myArray[x] floatValue]) {
tmp = myArray[x];
myArray[x] = myArray[y];
myArray[y] = tmp;
}
}
}
}
To call:
[self sortArray:myArray];
To declare with object scope, make a property in your #interface section
#interface myObject:NSObject
#property (nonatomic, strong) NSMutableArray* myArray;
#end
You will still need to create myArray before you can use it:
self.myArray = [[NSMutableArray alloc] init];
but you will be able to set and access it's values from anywhere inside the object thus:
self.myArray
And - if it is in the public header file #interface section - from outside the object thus:
myObject.myArray