Question

Unix and C

1) Which of the following command(s) can be used to check if the string "aabbcc" matches a pattern described by regex "aa.*" or not? (a) expr "aabbcc": 'aa.*" (b) echo "aabbccegrep 'aa.*' (c) expr match "aabbcc" 'aa.*" (d) egrep 'aa.*"< END aabbcc END 2) Which of the following is legal directives in C? (a) #include<stdio.h> (b) #include <stdio.h> (c) #include stdio.h (d) include stdio.h 3) If c is a variable of type char and i is a variable of int type, which one of the following statement is illegal? (a) c="65": (c) c-putcharO: (d) getchar(c);

Answer 1

The answer to the question is given below.

Ans1. Option C is correct.
expr match "aabbcc" 'aa.*'
match function gives the number of characters in the pattern if match is found else it returns 0

Ans2. Option A is correct.
Legal directive is
#include<stdio.h>
and all other options will give error.

Ans3.Option C and Option D are illegal.
c=putchar();
putchar() function is used to write a single character at the output stream. It must have one argument.
getchar(c)
getchar() function does not contains any arguments. It is used to read from the input stream.


Ans4.Option C is correct.
c is char type.
c='A'+'6'-'2'
c=69
c is char type so, it converts it to char so, c will become 'E'


Ans5.Option C ... Single Quotes....
when echoing a string, to inhibit wildcard substitution we can use single quotes.


Ans6.Option B is correct.
To create an executable file, the command is cc -o test test.c


Ans7. Option A,B and D are correct.
The correct option to execute the c file in Home directory
A. /Home/test
B ./test
D test


Ans8.Option B (1) is correct.
Here x=16 and y=3
x>>y here x is right shifted by 3
16/2^3=16=8=2 which is not 0 so, output is 1


Ans9. Option D is correct.
None of the above.
in func() function, we just right shifting x by y and after that checking if it is a 0 or non zero number.



Ans10.Option C is correct.
Option A and B gives the same result.
0 to 9
But Option C gives 1 to 9
becasue at startin checking condition makes it increase by 1


Ans11. Option D is correct.
The commands grouped together don't share the same I/O channel.





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