C interview Questions

 C Interview Questions 

1.  Why do we need to test weather it is memory leak or not?How are we going to know that?  

2.  how to find a given number is armstrong number or not in "c".?  

3.  If we develop a project in C, then how can we create an exe file of it?  

4.  whats is structure padding?Say a given structure Struct{int a;char c; float d;}the size of structure is  

5.  How to Write a recursive function to compute the number of sequences of n binary digits that do not contain  

6.  How to type a string without using printf function?  

7.  write a program which accepts a filename as a command line argument and reverses the contents of the  

8.  Write a program which accepts a filename as a command line argument and coverts all characters in the  

9.  I want a C program for : If the list of students’ information is represented by a linked list, write  

10.  I want a C program to rearrange a linked list so that nodes with even numbers as their information come

11. I want C program code for : Reverse the links of a linked list by traversing only once Input:The input  

12.  How to write a C program to find the power of 2 in a normal way and in single step?  

13.  What is a null macro? What is the differtents between a null pointer and a null macro? What is near  

14.  How do you write a program which produces its own source code as its output?  

15.  how to improve my c knowledge........  

16.  How to break cycle in circular single link list?  

                                        

17.  what does it mean-a[i]=i+i  

18.  Between a long pointer and a char pointer , which one consumes more memory? explain  

19.  what is wrong with the following c prog??char *s1 = "hello";char *s2 = "world";char *s3 = strcat(s1,  

20.  in c , main() is a function . and where is defined main() in c. bcz every function has three parts.

21.  write a program which sends a token on network and give the list of IP addresses of all the client currently  

22.  How can we open a image file through C program   

23.  What is the differece between #define and constant in C?  

24.  c program for delete a node from linked list  

25.  Where are the auto variables stored? What is the use of register variables?  

26.  What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?  

27.  How can you calculate number of nodes in a circular Linked List?  

28.  Can we use string in switch statement?  

29.  Output of this Programme please??main(){ int a[]={2,4,6,8,10}; int i;change(a,5);for(int                                                                                i=0;i  

30.  how to swap the content oftwo variables without a temporary variable  

31.  How do you write a C program which can calculate lines of code but not counting comments?  

32.  main(int x).............explaination on arguments passed thr' main  

33.  How to remove duplicate elements from an array  

34.  when function say abc() calls another function say xyz(), what happens in stack?  

35.  union u1{ int i; char c;}u2;u2.i=32767;u2.c='a';now the i value gets replaced.If we want to know the  

36.  What will be the output of the following program in UNIX OS with CC compiler and TC compiler?int main(){  

37.  How to find entered number is EVEN or ODD without using conditional statement(not using if.. else,if..  

38.  output of the following programvoid main(){unsigned i;i=100*400;printf(\  

39.  how can i find size of a variable without using sizeof() operator?  

40.  THE QUESTIONS ARE AS FOLLOWS:1.WRITE A \'C\' PROGRAM TO READ THE AGE OF 100 PERSONS AND COUNT THE NUMBER  

41.  what is far pointer?  

42.  c is a structural or highlevel or middle level language which one is correct answer  

43.  what are storage class in c  

44.  How to write a program such that it will delete itself after exectution?   

45.  how argc and argv works in the following main function?main(int argc,char *argv[]) { int n,i=0; while(argv[1][i]!=\'\\0\')  

46.  Why don\'t we add null pointer at the end of array of integer?How can we calculate the length of array  

47.  write a code for implementation of doubly linked list with use of single pointer in each node  

48.  What is use of macro arguments in c? what is major difference between normal macro definition and macro  

49.  main() { int i; clrscr(); printf("%d", &i)+1; scanf("%d", i)-1; }    

50.  main(int argc, char *argv[]) { (main && argc) ? main(argc-1, NULL) : return 0; }   

 51.  main(){ int i; float *pf; pf = (float *)&i; *pf = 100.00; printf("n %d", i);}  

52.  main(){ int i = 0xff ; printf("n%d", i  

53.  #define SQR(x) x * xmain(){ printf("%d", 225/SQR(15));}  

54.  union u{  struct st {       int i : 4;       int j : 4;       int k : 4;       int l; }st; int i;}u;main(){     

55.  union u{ union u { int i; int j; }a[10]; int b[10];}u;main(){ printf("n%d"  

56.  main(){ int i, j, *p; i = 25; j = 100; p = &i; // Address of i is assigned to pointer p printf("%f"  

57.  main(){ int i, j; scanf("%d %d"+scanf("%d %d", &i, &j)); printf("%d %d", i, j);}  

58.  main(){ char *p = "hello world"; p[0] = 'H'; printf("%s", p);}  

59.  main(){ char * strA; char * strB = I am OK; memcpy( strA, strB, 6);}  

60.  How will you print % character?  

61.  const int perplexed = 2;#define perplexed 3main(){ #ifdef perplexed #undef perplexed #define  

62.  struct Foo{ char *pName;};main(){ struct Foo *obj = malloc(sizeof(struct Foo)); clrscr(); strcpy(obj->pName  

63.  struct Foo{ char *pName; char *pAddress;};main(){ struct Foo *obj = malloc(sizeof(struct Foo));clrscr();  

64.  main(){ char *a = "Hello "; char *b = "World";clrscr(); printf("%s", strcat(a,b));}  

65.  main(){ char *a = "Hello "; char *b = "World"; clrscr(); printf("%s", strcpy(a,b))  

  

66.  void func1(int (*a)[10]){ printf("Ok it works");}void func2(int a[][10]){ printf("Will this work?");}  

67.  main(){ printf("%d, %d", sizeof('c'), sizeof(100));}  

68.  main(){ int i = 100; clrscr(); printf("%d", sizeof(sizeof(i)));}  

69.  main(){ int c = 5; printf("%d", main||c);}  

70.  main(){ char c; int i = 456; clrscr(); c = i; printf("%d", c);}  

81.  main(){ if ((1||0) && (0||1)) { printf("OK I am done."); } else { printf("OK I am gone.");  

82.  main(){ signed int bit=512, mBit; { mBit = ~bit; bit = bit & ~bit ; printf("%d %d", bit, mBit);   

83.  Point out error, if any, in the following program main() {      int i=1;       

84.  What would be the output of the following program? main() {      int i=4;       

85.  What is the output of the following program?#define SQR(x) (x*x)main(){     int a  

86.  In which line of the following, an error would be reported? 1. #define CIRCUM(R) (3.14*R*R); 2. main()  

87.  We should not read after a write to a file without an intervening call to fflush(), fseek() or rewind  

88.  If the program (myprog) is run from the command line as myprog 1 2 3 , What would be the output? main(int  

89.  If the following program (myprog) is run from the command line as myprog 1 2 3, What would be the output?  

90.  If the following program (myprog) is run from the command line as myprog monday tuesday wednesday thursday  

91.  In the following code, what is p2? typedef int* ptr ptr p1, p2;   

92.  What would be the output of the following program? main() { int y=128; const int x=y; printf("%d"  

93.  Following declarations are sameconst char *s; char const *s;   

94.  What would be the output of the following program? main() { char near * near *ptr1; char near * far *ptr2;  

95.  Following declarations are different from one anotherconst char *const s; char const *const s;   

96.  If the following program (myprog) is run from the command line as myprog friday tuesday sunday,   

97.  If the following program (myprog) is run from the command line as myprog friday tuesday sunday, What  

98.  Would the following program compile? main() { int a=10,*j; void *k; j=k=&a; j++; k++; printf("n%u%u"  

99.  According to ANSI specifications which is the correct way of declaring main() when it receives command  

100.  What would be the output of the following program? main() { const int x=5; int *ptrx; ptrx=&x; *ptrx=10;  

  

101.  How to convert Stack in to Queue and v varsa ? c with data structure.  

102.  what do you mean by normalisation of pointers  

103.  A switch statement cannot includea) constants as arguments b) constant expression as argumentsc) string  

104.  What is the type of the variable b in the following declaration?#define FLOATPTR float*FLOATPTR a,b;a)  

105.  In the following code, in which order the functions would be called?x = f1(23,14)*f2(12/4)+f3();a)    f1  

  

106.  what is the draw back in using friend function in c++  

107.  How can send unlimited no of arguments to a function, eg printf function can take any no of arguments  

108.  How can you get the number of elements in an array allocated dynamically at runtime? For example -int  

109.  What is the difference between#include< >and#include" "  

110.  if compiler for c is written in c language, which is used to complie the compiler?  

 111.  How to perform matrix multiplication using Double linked lists? 

 

112.  what is pointer? 

 

113.  x) main(){ printf("%x",-1 

 

114.  ix) main(){ int i=3; switch(i) { default:printf("zero"); case 1: printf("one"); break;  

 115.  viii) main(){ char *p; printf("%d %d ",sizeof(*p),sizeof(p));} 

 116.  vii)7. main(){ int i=-1,j=-1,k=0,l=2,m; m=i++&&j++&&k++||l++; printf("%d %d %d %d %d",i,j,k,l,m);} 

117.  vi) main(){ extern int i; i=20;printf("%d",i);} 

118.  v) main(){ int c[ ]={2.8,3.4,4,6.7,5}; int j,*p=c,*q=c; for(j=0;j 

119.  iv) main() { static int var = 5; printf("%d ",var--); if(var) main(); } 

120.  iii) main(){ float me = 1.1; double you = 1.1; if(me==you)printf("I love U");else printf("I hate U") 

121.  ii) main(){ char s[ ]="man"; int i; for(i=0;s[ i ];i++) printf("\n%c%c%c%c",s[ i ],*(s+i),*(i+s),i[s]) 

 122.  All the programs are tested under Turbo C/C++ compilers. It is assumed that, Programs run under 

123.  Can a variable be both const and volatile?  

124.  What is #line used for?  

 

125.  Difference between Funtion to pointer and pointer to function 

  

126.   Can static variables be declared in a header file?  

127.  How many levels deep can include files be nested? 

128.  Which expression always return true? Which always return false? 

  

129.  When is a switch statement better than multiple if statements?  

130.  What is the difference between goto and longjmp() and setjmp()?  

131.  What is an lvalue?  

132.  Array is an lvalue or not?  

 

133.  What is page thrashing?  

 

134.  What is a const pointer?  

135.  When should the register modifier be used? Does it really help?  

 

136.  when should the volatile modifier be used?  

 

137.  How reliable are floating-point comparisons? 

  

138.  How can you determine the maximum value that a numeric variable can hold?  

139.  When should a type cast be used?  

  

140.  When should a type cast not be used?

141.  Is it acceptable to declare/define a variable in a C header?  

 

142.   What is the difference between declaring a variable and defining a variable?  

143.  What is the benefit of using const for declaring constants?  

144.  What is the easiest sorting method to use?  

145.  What is the quickest sorting method to use?  

   

146.  How can I sort things that are too large to bring into memory?  

  

147.  What is the easiest searching method to use?  

 

148.  What is the quickest searching method to use?  

 

149.  What is hashing?  

150.  How can I sort a linked list?   

 

151.  How can I search for data in a linked list?  

 

152.  How do you redirect a standard stream?  

  

153.  How can you restore a redirected standard stream?  

 

154.  What is the difference between text and binary modes?  

155.  How do you determine whether to use a stream function or a low-level function?  

  

156.  How can I open a file so that other programs can update it at the same time?  

157.  How can I make sure that my program is the only one accessing a file?  

  

158.  What is Preprocessor?  

 

159.  What is a macro, and how do you use it?  

 

160.  What will the preprocessor do for a program?  

161.  How can you avoid including a header more than once?  

 

162.  Can a file other than a .h file be included with #include?  

 

163.  What is the benefit of using #define to declare a constant?  

 

164.  What is the benefit of using an enum rather than a #define constant?  

165.  How are portions of a program disabled in demo versions?  

  

166.  Is it better to use a macro or a function?  

  

167.  What is the difference between #include <file> and #include “file”?  

 

168.  Can you define which header file to include at compile time?  

 

169.  Can include files be nested?  

  

170.  How can type-insensitive macros be created?  

171.  What are the standard predefined macros?  

 

172.  What is a pragma?  

   

173.  How do you override a defined macro?  

 

174.  How can you check to see whether a symbol is defined?  

 

175.  What is the difference between a string copy (strcpy) and a memory copy (memcpy)? When should each be 

 

176.  How can I convert a number to a string?  

 

177.  How can I convert a string to a number?  

 

178.  How do you print only part of a string?  

 

179.  What is indirection?  

 

180.  How many levels of pointers can you have?  

181.  What is a null pointer?  

182.  What is a void pointer?  

 

183.  Is NULL always defined as 0?  

 

184.  What does it mean when a pointer is used in an if statement?  

 

185.  Can you add pointers together? Why would you?  

 

186.  How do you use a pointer to a function?  

 

187.  When would you use a pointer to a function?  

188.  Why should we assign NULL to the elements (pointer) after freeing them?   

 

189.  Is it better to use malloc() or calloc()?  

190.  What is the difference between far and near?  

 

191.  When should a far pointer be used?  

 

192.  What is the stack?  

  

193.  Can the size of an array be declared at runtime?  

  

194.  What is the heap?  

 

195.  What is the difference between NULL and NUL?  

 

196.  What is a “null pointer assignment” error? What are bus errors, memory faults, and core dumps?  

 

197.  How can you determine the size of an allocated portion of memory?  

 

198.  Can math operations be performed on a void pointer?  

 

199.  How do you print an address?  

 

200.  Why should I prototype a function?  

201.  What is a static function?  

 

202.  Is it possible to execute code even after the program exits the main() function?  

 

203.  Is using exit() the same as using return?  

 

204.  Can the sizeof operator be used to tell the size of an array passed to a function?  

 

205.  Is it better to use a pointer to navigate an array of values,or is it better to use a subscripted array 

 

206.  What is the difference between a string and an array?  

 

207.  what is a modulus operator? What are the restrictions of a modulus operator? 

 

208.  why n++ executes faster than n+1? 

 

209.  Write the equivalent expression for x%8? 

 

210.  What is storage class and what are storage variable ? 

211.  What are the advantages of auto variables? 

 

212.  Diffenentiate between an internal static and external static variable? 

213.  What are advantages and disadvantages of external storage class? 

 

214.  Differentiate between an external variable definition and external variable declaration  S.No   

   

215.  Differentiate between a linker and linkage?  

 

216.  What are the characteristics of arrays in C?  

 

217.  When does the compiler not implicitly generate the address of the first element of an array? 

 

218.      What is modular programming?  

 

219.  What is a function and built-in function?  

 

220.  What is an argument ? differentiate between formal arguments and actual arguments?  

 

221.  What is the purpose of main( ) function? 

 

222.  What are the advantages of the functions?  

 

223.  what is a method? 

 

224.  What is a pointer value and address?  

 

225.  What is a pointer variable? 

 

226.  Are pointers integers? 

 

227.  How are pointer variables initialized?  

 

228.  What is static memory allocation and dynamic memory allocation?  

 

229.   What is the purpose of realloc( )? 

 

230.  Difference arrays and  pointers?