why are these two NSString pointers the same?
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I am new to objective c. i alloc and init two nsstring variables, and compare their pointers,but they are the same. the codes are as follows:

    NSString *s1 = [[NSString alloc] initWithString:@"hello world"];
    NSString *s2 = [[NSString alloc] initWithString:@"hello world"];
   
    if (s1 == s2) {
        NSLog(@"==");
    }else {
        NSLog(@"!=");
    }

what confuse me is that why s1 and s2 are the same?