C Interview Questions-7

71. What are the two forms of #include directive?
Ans:
1.#include”filename”
2.#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.

72. How would you use the functions randomize() and random()?
Ans:
Randomize( ) initiates random number generation with a random value.
Random( ) generates random number between 0 and n-1;

73. What do the functions atoi(), itoa() and gcvt() do?
Ans:
atoi( ) is a macro that converts integer to character.
itoa( ) It converts an integer to string
gcvt( ) It converts a floating point number to string

74. How would you use the functions fseek(), freed(), fwrite() and ftell()?
Ans:
fseek(f,1,i) Move the pointer for file f a distance 1 byte from location i.
fread(s,i1,i2,f) Enter i2 dataitems,each of size i1 bytes,from file f to string s.
fwrite(s,i1,i2,f) send i2 data items,each of size i1 bytes from string s to file f.
ftell(f) Return the current pointer position within file f.

The data type returned for functions fread,fseek and fwrite is int and ftell is long int.

75. What is the difference between the functions memmove() and memcpy()?
Ans: The arguments of memmove( ) can overlap in memory. The arguments of memcpy( ) cannot.

76. What is a file?
Ans: A file is a region of storage in hard disks or in auxiliary storage devices.It contains bytes of information .It is not a data type.

77. What are the types of file?
Ans: Files are of two types
1-high level files (stream oriented files) :These files are accessed using library functions
2-low level files(system oriented files) :These files are accessed using system calls

78. What is a stream?
Ans: 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.

79. What is meant by file opening?
Ans: 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.

80. What is FILE?
Ans: FILE is a predefined data type. It is defined in stdio.h file.