Question:What is C language? 

The C programming language is a standardized programming language developed in the early 1970s by Ken Thompson and Dennis Ritchie for use on the UNIX operating system. It has since spread to many other operating systems, and is one of the most widely used programming languages. C is prized for its efficiency, and is the most popular programming language for writing system software, though it is also used for writing applications.

Question:How to reduce a final size of executable? 

Size of the final executable can be reduced using dynamic linking for libraries.

Question:What are macros? What are its advantages and disadvantages? 

Macro is a Pre-processor.Major advantage of using the macro is to increase the speed of the execution of the program.
Major disadvantage of the macros are:
(i) No type checking is performed in macro. This may cause error.
(ii)  A macro call may cause unexpected results.

Question:How does a C program come to know about command line arguments? 

When we execute our C program, operating system loads the program into memory. In case of DOS, it first loads 256 bytes into memory, called program segment prefix. This contains file tables,environment segment, and command line information. When we compile the C program the compiler inserts additional code that parses the command, assigning it to the argv array, making the arguments easily accessible within our C program.

Question:What is modular programming? 

If a program is large, it is subdivided into a number of smaller
programs that are called modules or subprograms. If a complex
problem is solved using more modules, this approach is known as
modular programming

Question:Differentiate between a linker and linkage? 

A linker converts an object code into an executable code by linking together the necessary build in functions. The form and place of declaration where the variable is declared in a program determine the
linkage of variable.

Question:Define Operator, Operand, and Expression in 'C'? 

Operators are symbols which take one or more operands or expressions and perform arithmetic or logical computations.
Operands are variables or expressions which are used in operators to evaluate the expression.
Combination of operands and operators form an expression.

Question:What is difference between declaration and definition? 

During declaration we just specify the type and no memory is allocated to the variable. But during the
 definition an initial value is assigned and memory is allocated to the variable.

Question:What is use of #pragma inline directive in c language? 

#pragma inline only tells the compiler that source code of program contain inline assembly language code .In c we can write assembly language program with help of asm keyword.

Question:What are enumerations? 

They are a list of named integer-valued constants. Example:enum color { black , orange=4,yellow, green, blue, violet };This declaration defines the symbols “black”, “orange”, “yellow”, etc. to have the values “1,” “4,” “5,” … etc. The difference between an enumeration and a macro is that the enum actually declares a type, and therefore can be type checked.