objective c - Copying NSDate objects and releasing -

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if this:

nsdate *datestart; [datestart alloc];  // initialise date somewhere here..  ..  // modify start date. datestart = [chosendate copy];

should doing [datestart release] before assigning datestart pointer?

i'm c/c++ background , don't understand whole objectivec/ios garbage collection behaviour (if indeed there any). c background telling me should freeing initial nsdate object datestart pointing to. correct?

yes since allocated before should release before line 

//release before reassign [datestart release]; datestart = [chosendate copy];

also notice preferred allocation , initialization on same line, dont break them multiple lines

so this

nsdate *datestart; [datestart alloc];

would change to

nsdate *datestart = [[datestart alloc] init....];

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