C Programming Viva Questions

C Programming Viva Questions

• Keywords: Keywords are predefined words with specific meanings in C. Programmers cannot redefine them.

Variable Names

• Rules for variable names in C:
  • The first character must be a letter or underscore.
  • The name can contain letters, digits, and underscores.
  • Special symbols and spaces are forbidden.
  • Keywords (reserved words) are not permitted for variable names.

Return Type of main()

• The main() function in C returns an integer value (int).

Unary Operators

• Examples of unary operators in C: ++, --, sizeof.

Modulus Operator Example

• The result of 15 % 33 is 15.

Entry Controlled Loops

• Examples of entry controlled loops in C: while and for.

Identifiers

• Identifiers are names given to program elements like variables, functions, etc.

Keywords in C

• There are 32 keywords in C.

auto as a Keyword

• auto is a keyword in C.

Development of C

• C was developed in 1972 at Bell Laboratories.

Features of C

• C is a simple, fast, structured, extensible, and middle-level language.

Local Variables

• A variable declared inside a function or block is a local variable.

Global Variables

• A variable declared outside a function or block is a global variable.

scanf() Function

• The scanf() function is used for input. It reads integers, floating-point numbers, characters, and strings.

printf() Function

• The printf() function is used for output. It displays integers, floating-point numbers, characters, and strings.

Array Types

• Arrays in C can be one-dimensional or multidimensional.

Pointers

• A pointer is a variable that stores the address of another variable.

Structures

• A structure is a user-defined data type in C used to store multiple data types.

Unions

• A union is a user-defined data type that can store multiple data types. However, only one data type can be stored at a time. This is more memory-efficient than a structure in most cases when storing multiple data types.

Relational Operators

• Relational operators in C: <, >, <=, >=, ==, !=.

Operator Precedence

• Some operators have lower precedence than others in C.

Ternary Operator

• The ternary operator in C: ?:.

typedef

• typedef is used to create a new name for an existing data type.

Arrays

• An array is a collection of similar data types having a common name.

getch() and getche() Functions

• Both getch() and getche() are used for character input. However, getche() displays the input character on the screen while getch(), does not.

while and do-while Loops

• while loops are entry-controlled, meaning the condition is checked before each iteration.
• do-while loops are exit-controlled, meaning the condition is checked after each iteration. This ensures the block of code inside the loop executes at least once.

File Open Modes

• Commonly used file open modes in C (for text files): r, r+, w, w+, a.

conio.h Header File

• conio.h is a header file that provides console input/output functions and variables.

FILE as a Data Type

• FILE is not a data type in C, but rather a structure used for file operations in the stdio.h header file.

Bitwise Operators

• Bitwise operators in C: & (AND), | (OR), ^ (XOR), ~ (complement), << (left shift), >> (right shift).

Real Data Types

• Real data types in C: float, double, long double.

NULL Pointer

• A NULL pointer does not point to any memory location. It stores the NULL value.

String Comparison

• The function strcmp() compares two strings in C.

Literal Declaration

• const int num = 25; declares a literal integer constant.

Void Pointer

• A void pointer has no associated data type and can store the address of any type of data.

Operating System associated with C

• The Unix operating system is often associated with the development of the C programming language.

printf() function purpose

• printf() function is used to display output, including integers, floating-point numbers, characters, and strings.

Right to Left Associative Operators

• Some examples of operators with right-to-left associativity are unary operators, assignment operators, and conditional operators.

Octal Escape Sequence

• The octal escape sequence in C is \nnn.

Switch Statement Data Types

• The values in the switch statement should be an integer or character data type.

Storage Class for Global Scope

• The extern storage class controls the scope of a global variable.

Less Memory Usage

• Unions generally use less memory than structures when storing multiple data types since they all share the same memory location.

Boolean Data Type

• The bool keyword is used to declare a boolean data type in C.

Call by Value vs. Call by Reference

• Call by value: The function works on a copy of a variable. Original variables remain unchanged.
• Call by reference: The address of the variable is passed to the function, affecting the original variable in the calling function.

Test your knowledge on key concepts of C programming with this quiz. Covering topics like variable names, unary operators, and keywords, this quiz is essential for beginners and anyone brushing up on their C skills. Challenge yourself and see how well you understand the fundamentals of C.