OBJECTIVE-C----Fast enumeration, array sorting

Directly on the code:

/ *
         * Quick enumeration
         *
         * /
        NSLog (@ "++++++++++++++++++");

        NSArray * testArray = @ [@ 1, @ 2, @ 3, @ 4, @ 5];
        // Iterate through array elements by fast enumeration
        for (NSArray * object in testArray) {
            NSLog (@ "% @", object);
        }
        // Use id when in doubt
        for (id object in testArray) {
            NSLog (@ "% @", object);
        }

        // Quickly traverse the collection
        for (id object in set1) {
            NSLog (@ "% @", object);
        }

        // Quickly traverse the dictionary (get the keys of the dictionary)
        // Directly traverse the dictionary to get each key of the dictionary, you can get the corresponding value by traversing the obtained keys
        for (id object in dic1) {
            NSLog (@ "% @", object);
        }
        // dic1 [key] can get the corresponding value, this is a syntactic sugar, equivalent to [dic1 objectForKey: key]
        for (NSString * key in dic1) {
            NSLog (@ "dictionary [% @]:% @", key, dic1 [key]);
        }

        / *
         * Array Sort
         *
         * /

        // Note that when initializing the array, all array element objects have the same type, and an error will occur as follows: @ [@ 1, @ 2, @ "5", @ 3, @ 4]
        NSArray * array1 = @ [@ 1, @ 2, @ 5, @ 3, @ 4];
        // Use the array sort method to sort the array in ascending order
        NSArray * resultArray = [array1 sortedArrayUsingSelector: @selector (compare :)];
        NSLog (@ "% @", resultArray);

        Student * stu1 = [Student studentWithName: @ "wang" score: @ 85];
        Student * stu2 = [Student studentWithName: @ "zhen" score: @ 95];
        Student * stu3 = [Student studentWithName: @ "gang" score: @ 65];
        NSMutableArray * stus = [NSMutableArray array];
        [stus addObject: stu1];
        [stus addObject: stu2];
        [stus addObject: stu3];

        [stus sortedArrayUsingSelector: @selector (scoreAscending :)];
        NSLog (@ "% @", stus);
        [stus sortedArrayUsingSelector: @selector (scoreDescending :)];
        NSLog (@ "% @", stus);
        [stus sortedArrayUsingSelector: @selector (nameAscending :)];
        NSLog (@ "% @", stus);
        [stus sortedArrayUsingSelector: @selector (nameDescending :)];
        NSLog (@ "% @", stus); 

OBJECTIVE-C----Fast enumeration, array sorting