Some examples of programs using arrays in Objective-C.

1. Computer Science Large Practical:
Arrays in Objective-C
Stephen Gilmore
School of Informatics
Friday 2nd November, 2012
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2. Experience report
The Desktop Team, in the University’s Information Services
department have asked for feedback from you regarding your
experiences (good or bad!) with Xcode in the Main Library IS Open
Access Lab.
This will help inform their plans for future academic years.
What has been your experience?
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3. Programming with arrays in Objective-C
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4. Inspecting an array
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5. The XML representation
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6. Sorting an array
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7. The sorted array
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8. The output in the console
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9. Everything OK? What about “Build and Analyze”?
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10. Handling arrays (1/2)
#import <Foundation/Foundation.h>
int main (int argc, const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc]
init];
NSLog(@"Hello, arrays!");
NSArray * myArray = [[NSArray alloc]
initWithObjects:@"foo",@"bar",@"baz",nil];
for(NSString * myStr in myArray) {
NSLog(@"-- %@", myStr);
}
[myArray writeToFile:@"myArray.plist" atomically:YES];
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11. Handling arrays (2/2)
NSArray *sortedArray = [myArray
sortedArrayUsingSelector:@selector(
caseInsensitiveCompare:)];
[sortedArray writeToFile:@"sortedArray.plist"
atomically:YES];
for(NSString * myStr in sortedArray) {
NSLog(@"---- %@", myStr);
}
[pool drain];
return 0;
}
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12. Object allocation and arrays
Arrays in Objective-C are not generic arrays: they can contain
different kinds of objects.
The nil value at the end is a terminator, signalling the end of the
array.
You can release an object as soon as you add it to an array because
the array allocates its own memory for the object by calling retain on
all objects which are added to it.
arrayWithObjects auto releases from memory so you do not have
to release the array yourself.
If we replace [NSArray alloc] initWithObjects with
arrayWithObjects then this should solve our memory leak.
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13. “Build and Analyze” finds no potential leaks now
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14. Mutable arrays
NSArray objects are not mutable so we cannot update their contents.
To have an array which we can update we should use
NSMutableArray.
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15. Declaring and using mutable arrays
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16. Output from the program
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