Better way to handle arrays in Objective-C? - iphone

Question

Please let me preface this question with an apology. I am very new to Objective C. Unfortunately, I have a very tight timeline on a project for work and need to get up to speed as fast as possible.
The code below works. I am just wondering if there is a better way to handle this... Maybe something more Cocoa-ish. The entire purpose of the function is to get an ordered list of positions in a string that have a certain value.
I fell back on a standard array for comfort reasons. The NSMutableString that I initially declare is only for testing purposes. Being a complete noob to this language and still wrapping my head around the way Objective C (and C++ I guess) handles variables and pointers, any and all hints, tips, pointers would be appreciated.
NSMutableString *mut = [[NSMutableString alloc] initWithString:#"This is a test of the emergency broadcast system. This is only a test."];
NSMutableArray *tList = [NSMutableArray arrayWithArray:[mut componentsSeparatedByString:#" "]];
int dump[(tList.count-1)];
int dpCount=0;
NSUInteger length = [mut length];
NSRange myRange = NSMakeRange(0, length);
while (myRange.location != NSNotFound) {
myRange = [mut rangeOfString:#" " options: 0 range:myRange];
if (myRange.location != NSNotFound) {
dump[dpCount]=myRange.location;
++dpCount;
myRange = NSMakeRange((myRange.location+myRange.length), (length - (myRange.location+myRange.length)));
}
}
for (int i=0; i < dpCount; ++i) {
//Going to do something with these values in the future... they MUST be in order.
NSLog(#"Dumping positions in order: %i",dump[i]);
}
text2.text = mut;
[mut release];
Thanks again for any replies.

Answer 1

There is not great way to do what you are trying to do. Here is one way:
// locations will be an NSArray of NSNumbers --
// each NSNumber containing one location of the substring):
NSMutableArray *locations = [NSMutableArray new];
NSRange searchRange = NSMakeRange(0,string.length);
NSRange foundRange;
while (searchRange.location < string.length) {
searchRange.length = string.length-searchRange.location;
foundRange = [string rangeOfString:substring options:nil range:searchRange];
if(foundRange.location == NSNotFound) break;
[locations addObject:[NSNumber numberWithInt:searchRange.location]];
searchRange.location = foundRange.location+foundRange.length;
}

Answer 2

This might be a little more streamlined (and faster in terms of execution time, if that matters):
const char *p = "This is a test of the emergency broadcast system. This is only a test.";
NSMutableArray *positions = [NSMutableArray array];
for (int i = 0; *p; p++, i++)
{
if (*p == ' ') {
[positions addObject:[NSNumber numberWithInt:i]];
}
}
for (int j = 0; j < [positions count]; j++) {
NSLog(#"position %d: %#", j + 1, [positions objectAtIndex:j]);
}