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3.  DESCRIBE ABOUT HISTORY OF C PROGRAMMING LANGUAGE.

C programming language is a structure oriented programming language, was developed at Bell Laboratories in 1972 by Dennis Ritchie. C language features were derived from earlier language called “B” (Basic Combined Programming Language – BCPL)

• In earlier days, programs were written in assembly level language. So, it had happened to write very big programs to perform specific tasks using assembly code.
• But, ‘B’ language could perform the same task in few lines of program and it was faster than assemble language code.
• But, B language did not support some features like data types and structures etc. So, this was a drawback of B language. So, Dennis Ritchie developed C language by keeping most part of the B language and adding many features that produced powerful and effective outputs.
• So, C language was invented for implementing UNIX operating system. Most of the UNIX components were rewritten in C.
• In 1978, Dennis Ritchie and Brian Kernighan published the first edition  “The C Programming Language” and commonly known as K&R C
• In 1983, the American National Standards Institute (ANSI) established a committee to provide a modern, comprehensive definition of C. The resulting definition, the ANSI standard, or “ANSI C”, was completed late 1988.
• C89/C90 standard – First standardized specification for C language was developed by American National Standards Institute in 1989. C89 and C90 standards refer to the same programming language.
• C99 standard – Next revision was published in 1999 that introduced new futures like advanced data types and other changes.
• C11 standard adds new features to C and library like type generic macros, anonymous structures, improved Unicode support, atomic operations, multi-threading, and bounds-checked functions. It also makes some portions of the existing C99 library optional, and improves compatibility with C++.
• Embedded C includes features not available in normal C like fixed-point arithmetic, named address spaces, and basic I/O hardware addressing.

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More C interview questions and answers:

1. What is C language?
2. Who developed C language?
3. Describe about history of C programming language.
4. Where is C programming language used or uses of C language?
5. What is the difference between C and C++?
6. What is the difference between top down approach and bottom up approach in programming languages?
7. What is the difference between C and Java?
8. C language has been developed in which language?
9. Which year C language is developed?
10. What is meant by programming language and give some examples?
11. Describe about C standards.
12. What are the key features of C language or what are the characteristics of C language?
13. What is embedded C?
14. Which level is C language belonging to?
15. What do you mean by high level, middle level and low level languages and give an example for each?
16. What is the difference between structured oriented, object oriented and non-structure oriented programming language?
17. What is compiler?
18. What is the difference between assembler, compiler and interpreter?
19. What is printf()?
20. What is scanf()?
21. What is meant by protocol?
22. Execution of a C program starts from which function?
23. What are all the sections that a C program may have and must have?
24. What is IDE?
25. List out some of C compilers.
26. What is header file in C language?
27. Is C language case sensitive?
28. What is Macro? Why do we use macro?
29. What is data type in C?
30. What is the difference between int, char, float and double data types?
31. What is the use of sizeof() function in C?
32. What is modifier in C?
33. What are different types of modifiers in C?
34. What is enum in C?
35. What is void in C?
36. What is token in C?
37. What are the types of C tokens?
38. What is identifier in C?
39. What is keyword in C?
40. List out some keywords available in C language.
41. What is constant in C?
42. What are the types of constants in C?
43. What is variable in C?
44. What is the difference between constant and variable in C?
45. Can variable name start with numbers?
46. What is the difference between variable declaration and variable definition in C?
47. What are the different types of variable in C?
48. What is local variable in C?
49. What is global variable in C?
50. What is environment variable in C?
51. What is operator in C?
52. What are the different types of operator in C?
53. What is the syntax for ternary operator in C?
54. What is arithmetic operator in C?
55. What is assignment operator in C?
56. What is the relational operator in C?
57. What is the logical operator in C?
58. What is the bitwise operator in C?
59. What are all decision control statements in C?
60. What are all loop control statements in C?
61. What is the difference between while and do-while loops in C?
62. What is the difference between single equal “=” and double equal “==” operators in C?
63. What is the difference between pre increment operator and post increment operator?
64. What is the difference between pre decrement operator and post decrement operator?
65. What is “&” and “*” operators in C?
66. What will happen if break statement is not used in switch case in C?
67. Why is default statement used in switch case in C?
68. What is the use of “goto” statement?
69. What value will be assigned to the variable X if a = 10, b = 20, c = 30, d = 40 for the expression X = a/b+c*d-c?
70. What is the value assigned to the following variables? int X1 = 13/3; int X2 = 13%3;
71. What is the difference between auto variable and register variable in C?
72. What is the difference between auto variable and static variable in C?
73. Where should type cast function not be used in C?
74. How many arguments can be passed to a function in C?
75. What is static function in C?
76. If you want to execute C program even after main function is terminated, which function can be used?
77. Is it possible to call atexit() function more than once in a C program?
78. What is exit() function in C?
79. What is the difference between exit() and return() in C?
80. What is the use of “#define” in C?
81. What is the syntax for comments in C?
82. What is “##” operator in C?
83. What is pragma in C? Or how will you execute functions before and after main function in C program?
84. How will you override an existing macro in C?
85. How to check whether macro is defined or not in a C program?
86. What is the difference between memcpy() and strcpy() functions in C?
87. What is the difference between memcpy() and memmove() functions in C?
88. Is there any inbuilt library function in C to remove leading and trailing spaces from a string? How will you remove them in C?
89. What is the difference between strcpy() and strncpy() functions in C?
90. Can array subscripts have negative value in C?
91. What is the difference between array and string in C?
92. What is pointer in C?
93. What is null pointer in C?
94. What is NULL in C?
95. What is void pointer in C?
96. What is dangling pointer in C?
97. What is wild pointer in C?
98. What is file pointer in C?
99. When can void pointer and null pointer be used in C?
100. What is const pointer in C?

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