definition

As I know, an array needs to have a specific size before compiling time in c. I wonder why this code still works? int s; printf("enter the array size: "); scanf("%d",&s); int a[s]; // Isn't s value determined at run time? Array sizes need to be known with ANSI 89 C. The 99 version of the spec removed this limitation and allowed for variable sized arrays. Here is the documentation no the GNU version of this feature http://www.cs.utah.edu/dept/old/texinfo/glibc-manual-0.02/library_toc.html#SEC49 If you need to allocate an array with dynamic size, you have to get it from the heap, with malloc().

Can someone give me an example of the Single Responsibility Principle? I am trying to understand what it means, in practice, for a class to have a single responsibility as I fear I probably break this rule daily. Check out the Solid description . Unless you ask for something more specific, it will be hard to help more. Single responsibility is the concept of a Class doing one specific thing (responsibility) and not trying to do more than it should, which is also referred to as High Cohesion. Classes dont often start out with Low Cohesion, but typically after several releases and different

I have a pre-existing table, containing 'fname', 'lname', 'email', 'password' and 'ip'. But now I want an auto-increment column. However, when I enter: ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT I get the following: #1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key Any advice?:) Muhammad Asif Mahmood Try this ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY If you don't care whether the auto-id is used as PRIMARY KEY , you can just do ALTER TABLE `myTable` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST; I just