// NSValue能够将c类型转换为Objective-C对象，如NSRange，CGPoint。CGSize，CGRect，CGVector，UIEdgeInsets，UIOffset

    NSRange range = NSMakeRange(0, 1);

    NSValue *rangeValue = [NSValue valueWithRange:range];

    // NSValue转换NSRange

    NSRange valueToRange = [rangeValue rangeValue];

    // 自己定义的结构体

    typedef struct {char *name; float score;} Student;

    Student studentA = {"xiao ming", 85.0};

    NSValue *studentValue = [NSValue value:&studentA withObjCType:@encode(Student)];

    // NSValue转换Student

    Student valueToStudent ;

    [studentValue getValue:&valueToStudent];