C_01 Introduction to C Language | C Programming Tutorials — Transcript

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1. 0:00So I'm going to start a course on
2. 0:01programming in C language and this is
3. 0:03the first video. So I'm going to discuss
4. 0:05some basic things in this video like
5. 0:07what is need of programming, why do you
6. 0:09write programs, what is need of writing
7. 0:11these programs, what is need of
8. 0:12programming languages and then we will
9. 0:14come to C language. Right? So now let us
10. 0:17discuss what is need of programming why
11. 0:19do you write programs. C computer is
12. 0:21what it's you can say a machine or you
13. 0:23can say a general purpose machine. The
14. 0:25use of computer is what? Which can be
15. 0:27which can perform any task. Any
16. 0:29computational task not any task any
17. 0:32computational task it can perform.
18. 0:34Right? But how do you communicate with
19. 0:36computer? Like suppose if you want to
20. 0:39add two numbers then it's not like that
21. 0:41you will say hey computer I want to add
22. 0:44two numbers four and five. So tell me
23. 0:46what is the addition of four and five.
24. 0:48No computer will not understand your
25. 0:51language. So now what you will do? We
26. 0:54will write some instructions you can say
27. 0:56sequence of instructions and we will
28. 0:58give those sequence or set of
29. 1:00instructions to computer and then
30. 1:03according to that computer will perform
31. 1:05your task. Right? So those set of
32. 1:08instruction are what? Program. Sequence
33. 1:10of instructions are what? Programs.
34. 1:12Right? That is why if you want that your
35. 1:15computer will perform some task for you,
36. 1:17you have to write programs. Right? That
37. 1:19is why we need to write programs. Fine.
38. 1:22But now see uh the language of computer
39. 1:24is what? Binary language. I hope
40. 1:26everybody know 0 and one computer can
41. 1:28understand only zero and one binary.
42. 1:32So if you write like if you write
43. 1:35instructions in English language, Hindi
44. 1:37language or in any language computer
45. 1:39will not understand then what we will do
46. 1:42that also we'll discuss how that
47. 1:44language how that program will be
48. 1:46converted into 0 and one and then
49. 1:48computer will perform your task. Fine.
50. 1:50So basically you can say what computer
51. 1:53run by programs. Computer is nothing
52. 1:55without programs. It cannot do anything
53. 1:57without programs. When you purchase a
54. 2:00new laptop or computer that is already
55. 2:02you know many programs are already there
56. 2:04in uh that programs or you can sorry in
57. 2:07your computer like some system programs
58. 2:10application programs or you must have
59. 2:12heard about system softwares application
60. 2:14software. Software is what? Definitely
61. 2:16uh it is a set of programs right? So
62. 2:18what system programs means what they are
63. 2:20going to manage uh that system resources
64. 2:23they are going to manage the hardware
65. 2:25and application programs or application
66. 2:27softwares are what they are basically
67. 2:30used to perform your task your f
68. 2:32favorite task like um web browser is
69. 2:35application software and text editor in
70. 2:38which you you can edit you can write
71. 2:40text you can edit text MS office that is
72. 2:43also a application software right but
73. 2:46suppose if you want computer to perform
74. 2:49your task any specific task according to
75. 2:52that you have to write your own program
76. 2:54and you have to submit that program you
77. 2:56have to give that program to computer
78. 2:58and then computer will understand your
79. 3:00program or you can say those sequence of
80. 3:02instructions and according to that will
81. 3:04give you some output right so now how do
82. 3:07you write programs like it's not like in
83. 3:10simple English language we'll write
84. 3:11programs and submit to computer no it is
85. 3:14not going to understand so for that
86. 3:16thing we need programming languages
87. 3:19right see when we communicate with each
88. 3:21other like if I want to communicate with
89. 3:24you then the language is maybe English
90. 3:26Hindi right so and for communication
91. 3:29what first of all you need to understand
92. 3:31the the alphabets first we we uh study
93. 3:35what ABCD and then words then we frame
94. 3:39sentences by using grammars and all
95. 3:41right and then we communicate then we
96. 3:43frame sentences and then we communicate
97. 3:45with each
98. 3:47Same thing in language also you need to
99. 3:49learn something before writing the
100. 3:52programs like the characters uh
101. 3:55character set of that language keywords
102. 3:58and some syntaxes and some rules right
103. 4:01and then we can write programs and then
104. 4:03we can interact with computers right but
105. 4:07the point here is what computer can
106. 4:09understand only zero and one and you are
107. 4:10writing programs in what if suppose C
108. 4:13language we take example of C language
109. 4:15anguage then definitely we are not going
110. 4:17to write like 0 1 0 0 1 suppose I write
111. 4:20this one this is a bunch of zeros and
112. 4:23one but we are not able to understand
113. 4:25what is meaning of this thing right but
114. 4:27maybe computer can understand obviously
115. 4:29computer will understand because it is
116. 4:31language of computer right so we write
117. 4:34what hash include stdioh hash include
118. 4:37cohach then void main then integer ab
119. 4:40int then print f scan f and everything
120. 4:44so That program first of all have to be
121. 4:48converted into this language machine
122. 4:52language 0 and one form and then
123. 4:55computer will execute your program or
124. 4:58more specifically I would say CPU
125. 5:03because it is what processor central
126. 5:06processing unit. This is processor. This
127. 5:08is you can say heart of computer. the
128. 5:10calculation, the computation, the task
129. 5:12which you are going you need to perform
130. 5:14on computer that is going to be
131. 5:16performed by CPU more specifically if I
132. 5:19will say then CPU will give you output
133. 5:23right so if you write program in this
134. 5:26format this is what machine level
135. 5:27language I hope you have heard about
136. 5:29machine level languages assembly level
137. 5:31languages then highle languages or
138. 5:32low-level languages middle level
139. 5:34languages right but we will uh generally
140. 5:37prefer to call highle languages right
141. 5:39high Level languages means the C, C++,
142. 5:42Java these are understandable by human
143. 5:45because if we write this if we see at
144. 5:48this code then we are not going we will
145. 5:50not understand what is this. So this is
146. 5:52machine level language right but before
147. 5:55invention of these highle languages they
148. 5:57used to write programs in this format.
149. 6:00See you can imagine how tough it was at
150. 6:03that time to write program in this
151. 6:06language machine language because see
152. 6:08and this is what this is according to
153. 6:10you know some those uh CPU architecture
154. 6:13some set of specifications are there
155. 6:15which some architecture is there which
156. 6:17CPU follows uh I think you will or maybe
157. 6:21you have studied the subject CO
158. 6:23organization and architecture in that uh
159. 6:25you must have studied those
160. 6:27architectures right so according to
161. 6:30those specification, those archite
162. 6:31architecture of the CPU, this code will
163. 6:35differ. It means it is machine
164. 6:37dependent. In one computer, the same
165. 6:40program like addition of two numbers.
166. 6:42Let us suppose in at one CPU, right?
167. 6:46Suppose according to this CPU
168. 6:48architecture or the specifications, the
169. 6:50instruction can be given in 20 bits like
170. 6:5320 bits, right? And first four bit are
171. 6:57for um operator. I hope everybody know
172. 6:59like I suppose I'm writing 1 + 2 1 and
173. 7:02two these are operants and plus is
174. 7:03operator here we write as op code
175. 7:06suppose these first four bits are for
176. 7:08this plus to indicate this plus and
177. 7:11suppose here plus I'll write like 0 0 1
178. 7:140 0 1 0 so computer will understand that
179. 7:19this is for plus
180. 7:22that he has to perform plus operation
181. 7:24right and then next eight bits are for
182. 7:27one this operant and next eight bit are
183. 7:29for second operant. We will write these
184. 7:32two operants into binary form right like
185. 7:350 0 0 7 0 and 1 and two how you will
186. 7:40write this is two in binary form so that
187. 7:42we will write here and when we submit
188. 7:44this instruction then
189. 7:47the CPU will perform addition of of one
190. 7:50one and two and it will give you the
191. 7:51result right and suppose the according
192. 7:54to the specification of CPU to second
193. 7:56processor
194. 8:00Maybe their plus is 0 0 0 1 right or
195. 8:06maybe the length of the instruction is
196. 8:08uh something else not 20 bits. So it's
197. 8:12not easy to write programs in machine
198. 8:14language because it it is dependent on
199. 8:16that machine to machine. So it is not
200. 8:19the programs are not portable in one
201. 8:21machine. If you are writing program for
202. 8:22addition then again you have to write
203. 8:25rewrite that program for second machine.
204. 8:27It's not like that the same program will
205. 8:29run on second machine. That is very
206. 8:31difficult. Then assembly level languages
207. 8:34come. These levels we'll discuss uh in a
208. 8:36separate video with more details. And
209. 8:38after that highle languages come to
210. 8:40overcome these limitations to add
211. 8:43portability concept so that one program
212. 8:45on one machine we write and that program
213. 8:48can easily be ported to second machine.
214. 8:50Means we can uh we can run that program
215. 8:54same program on second machine also
216. 8:56without any modification or maybe you
217. 8:57can say with few modifications
218. 9:00right. So now let us discuss what is C
219. 9:02language. See it was developed by Dennis
220. 9:05Richie in 1972 where Bell Laboratories
221. 9:09the headquarter of these Bell Labs are
222. 9:11where in New Jersey US right and it is
223. 9:15before C the language was developed B
224. 9:17language. So you can say C is what
225. 9:21successor of B language. It was
226. 9:23developed by uh Ken Thompson right and
227. 9:26why C language was developed at that
228. 9:29time basically the main purpose was to
229. 9:32uh you know uh write operating system
230. 9:35that is Unix operating system that was
231. 9:38already written in B language but there
232. 9:41was some uh limitations. So to overcome
233. 9:43those limitations because C was more
234. 9:46powerful than B language right. So they
235. 9:49used to uh write the kernel of Unix
236. 9:53operating system they used this language
237. 9:55C language. So C is basically you can
238. 9:58say it's a system programming languages
239. 9:59language. Many softwares have been
240. 10:02written in C language. Oracle Android
241. 10:05the core libraries of Android was
242. 10:07written in C language. Major part of web
243. 10:10browser is written in C language. Device
244. 10:12drivers written in C language and Unix
245. 10:16operating system. So C is you can say
246. 10:18the most popular programming language
247. 10:20and during 1980s C was the most widely
248. 10:24used programming language and in 1989 it
249. 10:28was standardized by ANSI that is why uh
250. 10:32after that it is called ANSIC and see
251. 10:36how the computer is going to understand
252. 10:37what whatever we will write in C
253. 10:39language because here it is not machine
254. 10:41level language here we are not going to
255. 10:42write the bunch of zeros and ones right
256. 10:45so first of all The program program that
257. 10:47you will write in C language that is to
258. 10:50be converted into that object uh file or
259. 10:53object code or you can say that machine
260. 10:55code zeros and ones and who is going to
261. 10:58convert it compiler that is why it is
262. 11:01known as compiled language right and the
263. 11:04program is uh written like the name of
264. 11:06the program is ABC suppose and the
265. 11:09extension of C program is do C right so
266. 11:13uh the compiler is going to convert it
267. 11:15into that OBJ file, object code, machine
268. 11:18level code and then the CPU will run
269. 11:20this uh program. The whole process we
270. 11:23are going to discuss in a separate video
271. 11:25like the basic the execution how the
272. 11:27program is going to be executed when it
273. 11:29is going to be converted in object file
274. 11:31by uh whom and what is the role of that
275. 11:34linker and loader and executable file
276. 11:37when executable file will be uh formed
277. 11:39and then how you will get the output
278. 11:42that also we'll discuss in a separate
279. 11:44video.
280. 11:45complete process. One more uh thing is
281. 11:48interpreter and the main task of
282. 11:50interpreter is also to convert this
283. 11:52program highle program into object code.
284. 11:55But the difference we'll see in a
285. 11:56separate video. So now that's it for
286. 11:58this video. Now I'm going to see in the
287. 11:59next video. Till then bye-bye. Take
288. 12:01care.