C Programming Language is one of the oldest languages which is still one of the popular languages around. Now, C has several applications wherein this language is used, and they are:
Operating Systems, Embedded Systems, GUI, new programming platforms could be created using C, Gaming, Animation, etc.
If you wish to learn C to be able to design any of these applications, I recommend you check out the C Language online course from Intellipaat. Also, check out the following YouTube video on C Programming Full Course.
Back