Question : What modular programming?

Answer : 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 :  What is a function?

Answer : A large program is subdivided into a number of smaller programs or subprograms. Each subprogram specifies one or more actions to be performed for the larger program. Such sub programs are called functions.

Question :  What is an argument?

Answer : An argument is an entity used to pass data from the calling to a called function.

Question :  What are built in functions?

Answer : The functions that are predefined and supplied along with the compiler are known as builtin functions. They are also known as library functions.

Question :  Difference between formal argument and actual argument?

Ans: Formal arguments are the arguments available in the function definition. They are preceded by their own data type. Actual arguments are available in the function call. These arguments are given as constants or variables or expressions to pass the values to the function.

Question :  Is it possible to have more than one main() function in a C program ?

Ans: The function main() can appear only once. The program execution starts from main

Question : What is Difference between pass by reference and pass by value?

Answer : Pass by reference passes a pointer to the value. This allows the callee to modify the variable directly.Pass by value gives a copy of the value to the callee. This allows the callee to modify the value without modifying the variable. (In other words, the callee simply cannot modify the variable, since it lacks a reference to it.) 

Question : What is recursion?

Answer : A recursion function is one which calls itself either directly or indirectly it must halt at a definite point to avoid infinite recursion.