Why is Windows giving my hard disk the letter C and not A or B for example?

Wikipedia gives a good explanation about the logic of drive lettering:

Except for CP/M and early versions of MS-DOS, the operating systems assigns drive letters according to the following algorithm:

1. Assign the drive letter A: to the first floppy disk drive (drive 0), and B: to the second floppy disk drive (drive 1), if present.
2. Assign a drive letter, beginning with C: to the first active primary partition recognised upon the first physical hard disk.
3. Assign subsequent drive letters to the first primary partition upon each successive physical hard disk drive, if present within the system.
4. Assign subsequent drive letters to every recognised logical partition, beginning with the first hard drive and proceeding through successive physical hard disk drives, if present within the system.
5. Assign subsequent drive letters to any RAM Disk.
6. Assign subsequent drive letters to any additional floppy or optical disc drives.

It's a left over from the original PC designs. Originally PCs only had up to 2 floppy disk drives labelled A and B. Some time later hard disks got added and became drive C.

The hard disk letter is C because historically, drives A and B were for floppy disks. It has nothing to do with the language in which the operating system is written.

Ah, floppy disks, remember those?

You could spend a whole afternoon coding your latest killer app, then find that you couldn't save it because it was too big to fit on a 5.25" single density disk.

That was when floppies really were floppy. Thin and flimsy, usually in either 5.25" or 8" sizes, though the first internal drives that appeared in PCs were 5.25". As previously mentioned, the early versions of MS Dos used to automatically assign drive A: to the first floppy drive and B: to the second. Hard drives didn't even fit into PCs back then. You could buy a 5mb Winchester Hard Disk that weighed about 30Kg and came in a big external cabinet nearly the size of a modern mini tower pc.

If your PC had twin floppies you could type a command something like "copy a: b:" to copy the contents of drive A: to drive B:

But then that was all back in a time when Bill Gates was worth about $10,000!

Its because A and B used to be floppy drives back in the days when floppy drives were the norm and there were no hard-disks. The letter C was given to any hard disk that the user installed. The drives A and B have since then been reserved for floppy drives. This has nothing to do with programming languages.

The origins of drive letters

*But why the letter "C"? Why not "A" or "B"? Why not "Z?"*

Unsurprisingly, the answer lies in Microsoft's old DOS roots. Long before Windows existed, most PC-compatible computer systems had only one disk drive in it - a floppy disk drive. At the time, users would insert their DOS floppy disk into the computer just before they turned it on, and the computer would start, or "boot up" via the software on the floppy. As the first and often only disk drive installed in the computer, the floppy disk was assigned the first letter of the alphabet.

On computers running Windows or MS-DOS, the hard drive is labelled with the drive letter C, because it is the first available drive letter for hard drives. The computer reserves the A: and B: drive letters for the floppy disk drive and removable media, such as tape drives, even if none of these devices are installed in the computer. As you install other drives and create new partitions, they will be assigned to other drive letters after C, such as D, E, F, G, etc.

Source

I'd say that it's because the A: and B: drives were traditionally floppy drives and early computers required you to boot using a bootable floppy disk.

I strongly doubt if the lettering has anything to do with programming languages.

I think it's a kind of legacy from old versions of Microsoft Operating Systems where letters A and B were assigned to floppy drives.

Think DOS was working from floppy drive, and windows built on DOS continued the same drive letter convention ...

On computers running Windows or MS-DOS, the hard drive is labeled with the C: drive letter. The reason is because it is the first available drive letter for hard drives. The computer reserves A: and B: drive letters for the floppy disk drive and removable media, such as tape drives, even if these devices are not installed in the computer. As you install other drives and create new partitions, they are assigned to other drive letters after C, such as D, E, F, G, etc.