You can think of a computer program as a series of instructions to a computer. You need to be blunt and tell the computer what to do – there is no magic involved.
This can be done on different levels. On the lowest level there is machine code, the instructions that the processor hardware is designed to execute.
While it would execute very efficiently, this might not be the language of choice for your program if you don’t have a lot of time on your hands – or if you want your program to execute on different kinds of hardware.
Bugs (errors) in the program would be rather hard to find. Reusing code would be difficult, there would be a lot of copy & paste involved.
If we go up one level, to assembly language this is somewhat addressed by having macros that contains blocks of code that can be reused, and other useful constructs.
XOR EAX, EAX ; zero out eax MOV ECX, 10 ; loop 10 times Label: ; this is a label in assembly INX EAX ; increment eax LOOP Label ; decrement ECX, loop if not 0
It’s still rather far from what we consider a modern programming language – although all programs eventually will come down to executing as a series of machine code instructions on the hardware.
When we look at a programming language, it is often said that there is a level of abstraction in the language. Abstraction is defined to mean that we deal with ideas rather than events. The higher the level of the language the greater the level of abstraction.
Looking at one of the simplest C# programs:
class Program
{
static void Main(string[] args)
{
System.Console.WriteLine("Hello world!");
}
}
there is a very high level of abstraction just in this very simple example.
What we have done is expressed that we want to print the text Hello world! to the console (command prompt) of the user executing the program.
Imagine doing this in machine code. We’d have to output every single character of Hello world! to an I/O register that corresponds to the console – that would be different for almost every kind of hardware!
Instead we just say print Hello world!. Amazing.
If we go even further, there are ways to organize data (classes for example) that takes us further up the ladder of abstraction, and other ways of expressing our ideas in the forms of computer programs.
This, and more, will be covered in the courses on this site, so there are exciting times ahead!