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Q1. Explain the importance of C language.
Ans. 1. C is portable means program written for
one computer may run successfully on other computers.
2.
C is fast means the executable program obtained after compiling and linking run
very fast.
3.
C is compact i.e. the statements in C-language are generally short but are very
powerful; several operators can be combined together in just one statement.
4.
The C language has both the simplicity of
high-level language and low-level language.
Q2. What is the structure of ‘c’ program?
Ans. i) Any C program is the combination of
functions. main() is one such function.
ii) The set of
statements belonging to a function are enclosed within a pair of braces.
iii) Any variable
used in the program must be declared before using it.
iv) Any c statement
always ends with a ;
The structure of c
program is as follow:
# Preprocessor
directives
....................................
....................................
void main ()
{
body
of the main function;
........................;
........................; }
Q3. What are the relational operators
available in C?
Ans. The various
relational operators available in ‘C’ are: -
|
Operator
|
Description
|
|
>
|
Greater then
|
|
<
|
Less then
|
|
>=
|
Greater then and
equal to
|
|
<=
|
Less then and
equal to
|
|
==
|
Equal to
|
|
!=
|
No Equal to
|
Q4. What is the purpose of adding comments in
a program? Can comments span more then a line.
Ans. Comments are non-executable statements. With
the help of comments we can give description about the program or any
particular statement. Comments are enclosed with in /* and */. Any number of
comments can be given at any place in the program. Comments can't not be
nested.
A comment can be
split over more than one line, as in,
/* this is
comment */
Q5. What is the syntax of PRINTF function
of 'C'?
Ans. printf() is function, which is used to print
on the screen the value contained in a variable.
The
general form of printf statement is ,
printf
("format string",list of variable);
format
string could be ,
%f
for printing real values
%d
for printing integer values
%c
for printing character values
Q6. What is the syntax of nested if statement?
Ans. It is perfectly alright if we write an
entire if-else construct within either the body of the if statement or the body
of an else statement. This is called of 'nesting' of if statement. The syntax
is as follow:
if
(condition)
{
if (condition)
do this;
else
{
do this;
and this;
}
}
else
do this;
Q7. What
is the syntax of switch statement?
Ans. The control statement, which allows us to
make a decision from the number of choices, is called switch. Or more correctly
switch-case-default, since these three keywords go together to make up the
control statement. They most often appear as follows:
switch
(integer expression)
{
case constant 1:
do this;
case
constant 2:
do this;
case constant 3:
do this;
default:
do this;
}
Q8. What
is the syntax of FOR statement?
Ans. The FOR loop allows us to specify three
things about a loop in a single line:
a) Setting
a loop counter to an initial value.
b) Testing
the loop counter to determine whether its value has reached the number of
repetitions desired.
c) Increasing
the value of loop counter each time the program segment within the loop has
been executed.
The
general form of for statement is as under:
for
(initial counter; test counter; increment counter)
{
do this;
and this;
and
this;
}
Q9. What
is format specifier?
Ans. Format specifier is used to specify the data
type of the variable. The format specifiers for various data types are shown
below:
|
%d-------Integer
data
|
%c------Character
data
|
|
%f-------Floating
point data
|
%ld-----Long
Integer
|
Q10. What
is the scope of local variable?
Ans. The scope of local variable is that, the
variable is accessible with the block where it is declared. Local variable
can't be accessed outside of the block, which contains its declaration.
Q11. Which
are the conditional operators available in C?
Ans. The conditional operators ? and : are
sometimes called ternary operators since they take three arguments. In fact,
they form a kind of foreshortened if-then-else. Their general form is,
expression
1 ? expression 2 : expression 3
If
expression 1 is true then the value returned will be expression 2 otherwise the
value returned will be expression 3.
Q12. What are the formatted output statements of
C?
Ans. I/O functions can be of two types (i) formatted and (ii) unformatted functions.
The basic difference between them is that the formatted functions allow the
input read from the keyboard or the output displayed on the VDU to be formatted
as per our requirements. For example, if
values of average marks and percentage marks are to be displayed on the screen,
then details like where this output would appear on the screen, how many spaces
would be present between the two values, the number of places after the decimal
points etc. can be controlled using formatted functions. printf() and fprintf()
are formatted output functions in C.
Q13. What is pseudo code?
Ans. Pseudo code is programming code written in
general English language, so that no programmers can understand the code
properly.
Q14. Write a short note on type casting?
Ans. Type casting refers to enforcement of
explicitly converting the value of an expression to a particular data type. It
is used to convert the data type from lower data type to higher data type and
converse for temporary period. So that calculation can be performed with both
the data types. e.g.
void main()
{ int
a=5;float b;
printf(“value
of a %d”,a);
b=(float)a;
printf(“value of b %d”,b);
}
Q15. What
do you mean by type conversion?
Ans. In an expression there might be cases when
you need to involve different types of variable in a single expression. For example,
an expression may contain addition of two integers and the result is required
to be multiplied by a float. The expressions that contain variables and
constants are evaluated using the following methods, known as Type conversions.
The data types are required to be converted for easy calculation of the
expression. These conversions are implicitly done by the system.
Q16. What are the derived data types used in C?
Ans. The derived data types are
|
Arrays
(
array[10]) |
Functions (
function()) |
Enumerated
(
enumerated_variable) |
|
Pointers
(
*pointer) |
Structures (
structure.member) |
Union (
union_name.member) |
Q17. What do you mean by local and global
variables?
Ans.
Local variables: Local variables
are defined with in the pair of braces or between the body of the function. The
scope of the variable is with in the function when function finished they will
obsolete.
Global
variables: These variables defined out side all the
function. And can be used to any function with in the file because the scope of
these variable are global to the file.
Q18. Explain various programming techniques?
Ans. Programming techniques are used to make the
program simple, efficient, understandable and easy to maintain. The three
programming techniques commonly used are:-
Top
down design: - Using this design program is divided
into the smaller blocks, which can be linked and called whenever needed. The
programmers design the program in different levels and can be called any level
at any time.
Bottom
up design: - It is also designed in the same manner and
divide the whole program into the smaller blocks, but when it is called it
begins from the smaller block to the bigger till the program end.
Modular
design: - A level consists of one or more modules. The
first level is a complete main program and the module of the successive level
contains sub modules Execution is controlled by the main program
Q19. What is sizeof operator?
Ans. The sizeof operator returns the size, in
bytes, of given operand.
Syntax is: -
sizeof
(exp)
Example:
-
sizeof (float)
Result:
-
returns
value 4
Q20. Differentiate between expression and
statement.
Ans. An expression refers to variables, constants and operators. It
represents a single data item, such as a numbers or characters. One or more
operators may interconnect these variables or constants. In C, very complex
expressions can be solved easily. An algebraic expression in C is represented
as follows:
Algebraic expression: a x b – c x d
Its relative C expression will be written as: a * b – c* d.
Q21. What is the use of #define directives
statement?
Ans. Define directives are used to define macro
and the constants. This preprocessor starts with #(hash) symbol.
Q22. What is a
macro? How is it different from preprocessor?
Ans. The macro is substitution string that is
placed in a program. It is replaced by the definition when program is compiled.
It is different from preprocessor as preprocessor links the files with the
object code.
Q23. What do you mean by ternary operator?
Ans.
Both if and ? : (Ternary operator) perform
the same conditional operation, but ?: process fast as compare to the 'if'
statement. The ? (ternary condition) operator is a more efficient form
for expressing simple if statements.
We can also nested the ternary operator. It has the following form:
Condition? True: False
Q24. Distinguish between
unary and binary minus.
Ans. Unary operators work on one operand and binary operators work on
two operands. The unary operators negate the value of the operand
For example
Int a=5;
a=-a;
Then
the value of a is now –5
In case of binary minus it perform
arithmetic subtraction on the given operands
For example
Int a,b,c;
a=90;
b=80;
c=a+b
Q25. Differentiate between comparison and
equality operator.
Ans. A
character or symbol indicating a relationship between two or more values or
expressions called an operator. These operators include less than (<), less
than or equal to (<=), greater than (>), greater than or equal to
(>=), not equal (<>), and equal (==).
Q26. Explain
various types of errors with examples.
Ans. Syntax errors: The errors, which
occur due the incorrect way to write the code. It may be due the missing comma,
semi colon etc.
As
the line:
printf(hello);
will
show the error because string is not enclosed in " " .
Logical
error it is not due to any syntax mistake,
but due to incorrect logic. The compiler will not show the error due to this.
The programmers himself have to find and correct it.
As: for(I=10;I<5 span="span">
Here
the logic is wrong as I is already 10 which is never less then 5.
Q27. What is the syntax of while statement?
Ans. initialization of looping variable;
While
(conditional expression)
{
body of the
loop
....................
....................
....................
Increment/decrement;
}
Q28. What do you mean by conditional execution?
Ans. When execution of set of commands is based
upon some condition. This is known as conditional execution. Depending upon
true or false path we can have different set of instructions to execute.
Q29. What is difference between if and ? :
(Ternary operator)?
Ans. Both if and ?: operator perform the same
conditional operation , but ?: process fast as compare to the 'if' statement.
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