C Programing Questions And Answers

C Functions

Q. What is a function?
Ans: 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.

Q. What is an argument?
Ans: An argument is an entity used to pass data from the calling to a called function.

Q. What are built in functions?
Ans: The functions that are predefined and supplied along with the compiler are known as built-in functions. They are also known as library functions.

Q. What do the ‘c’ and ‘v’ in argc and argv stand for?
Ans: The c in argc(argument count) stands for the number of command line argument the program is
invoked with and v in argv(argument vector) is a pointer to an array of character string that contain the arguments.

Q.what are C tokens?
Ans: There are six classes of tokens: identifier, keywords, constants, string literals, operators and other separators.

Q. What are C identifiers?
Ans: These are names given to various programming element such as variables, function, arrays.It is a combination of letter, digit and underscore.It should begin with letter. Backspace is not allowed.

Q. Difference between syntax vs logical error?
Ans:
Syntax Error
1-These involves validation of syntax of language.
2-compiler prints diagnostic message.
Logical Error
1-logical error are caused by an incorrect algorithm or by a statement mistyped in such a way
that it doesn’t violet syntax of language.
2-difficult to find.

Q. Can we use any name in place of argv and argc as command line arguments ?
Ans: yes we can use any user defined name in place of argc and argv;

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

Q. In header files whether functions are declared or defined?
Ans: Functions are declared within header file. That is function prototypes exist in a header file,not function bodies. They are defined in library (lib).

Q. Is the allocated space within a function automatically deallocated when the function returns?
Ans: No pointer is different from what it points to .Local variables including local pointers variables in a function are deallocated automatically when function returns.,But in case of a local pointer variable ,deallocation means that the pointer is deallocated and not the block of memory allocated to it. Memory dynamically allocated always persists until the allocation is freed
or the program terminates.

Q. Are the variables argc and argv are always local to main?
Ans: Yes they are local to main.

Q. Can main () be called recursively?
Ans: Yes any function including main () can be called recursively.

Q. 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.

Q. 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.

Q. What is the difference between an enumeration and a set of pre-processor # defines?
Ans: There is hardly any difference between the two, except that #defines has a global effect (throughout the file) whereas an enumeration can have an effect local to the block if desired. Some advantages of enumeration are that the numeric values are automatically assigned whereas in #define we have to explicitly define them. A disadvantage is that we have no control over the size of enumeration variables.

Q. Write a program which employs Recursion?
Ans: int fact(int n) { return n > 1 ? n * fact(n – 1) : 1; }

Q.Write a program which uses Command Line Arguments?
Ans:
#include
void main(int argc,char *argv[])
{
int i;
clrscr();
for(i=0;i
printf(“\n%d”,argv[i]);
}