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C Programming Interview Questions and Answers Part 7

 

61.Can a Structure contain a Pointer to itself?

  • Yes such structures are called self-referential structures.

 

62.What is the difference between array and pointer?

  • Array:

    1. Array allocates space automatically.

    2. It cannot be resized

    3. It cannot be reassigned.

    4. size of (arrayname) gives the number of bytes occupied by the array.

 

  • Pointer:

    1. Explicitly assigned to point to an allocated space.

    2. It can be sized using realloc() 3-pointer can be reassigned.

    3. sizeof (p) returns the number of bytes used to store the pointer variable p.

 

63.What is the difference between syntax vs logical error?

  • Syntax Error:

    1. These involves validation of syntax of language.

    2. compiler prints diagnostic message.

  • Logical Error:

    1. logical error are caused by an incorrect algorithm or by a statement mistyped in such a way that it doesn’t violet syntax of language difficult to find.

 

64.What is preincrement and post increment?

  • ++n (pre increment) increments n before its value is used in an assignment operation or any expression containing it. n++ (post increment) does increment after the value of n is used.

 

65.What are the two forms of #include directive?

  • #include“filename”

  • #include - the first form is used to search the directory that contains the source file.

  • If the search fails in the home directory it searches the implementation defined locations.

  • In the second form ,the preprocessor searches the file only in the implementation defined locations.

 

66.What is the difference between the functions memmove() and memcpy()?

  • The arguments of memmove() can overlap in memory. The arguments of memcpy() cannot.

 

67.what is a stream?

  • A stream is a source of data or destination of data that may be associated with a disk or other I/O device.

  • The source stream provides data to a program and it is known as input stream.

  • The destination stream eceives the output from the program and is known as output stream.

 

68.What is meant by file opening?

  • The action of connecting a program to a file is called opening of a file.

  • This requires creating an I/O stream before reading or writing the data.

 

69.What is a file pointer?

  • The pointer to a FILE data type is called as a stream pointer or a file pointer.

  • A file pointer points to the block of information of the stream that had just been opened.

 

70.What are the advantages of using array of pointers to string instead of an array of strings?

  • Efficient use of memory.

  • Easier to exchange the strings by moving their pointers while sorting.

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