C

Question 1

What is C?

Answer 1

C is a general-purpose, procedural programming language developed by Dennis Ritchie in the early 1970s. It is widely used for system and application software.

Question 2

What’s the difference between C and C++?

Answer 2

C is a procedural programming language, while C++ supports both procedural and object-oriented programming (OOP) features. C++ is an extension of C.

Question 3

What is a complier?

Answer 3

A compiler is a tool that translates C source code into machine code or object code that the computer can execute.

Question 4

What are header files in C?

Answer 4

Header files in C contain function declarations, macros, and definitions that can be included in multiple files using #include. Common examples are stdio.h, stdlib.h, etc.

Question 5

What is the main() function in C?

Answer 5

The main() function is the entry point of every C program. It is where the execution of a C program begins.

Question 6

What is #include <stdio.h>?</stdio.h>

Answer 6

It is a preprocessor directive that includes the standard input/output library, allowing the program to use functions like printf and scanf.

Question 7

What is printf() used for?

Answer 7

printf() is used to print formatted output to the console.

Question 8

What is scanf() used for?

Answer 8

scanf() is used for formatted input, allowing users to input values into variables.

Question 9

What are variables in C?

Answer 9

Variables are containers that store data values. Each variable in C has a specific type which defines the kind of data it can hold.

The basic data types in C are:
int (integer)
float (floating-point numbers)
char (characters)
double (double-precision floating-point numbers)

Question 10

What are pointers in C?

Answer 10

Pointers are variables that store memory addresses of other variables. They allow for dynamic memory allocation and manipulation of data at specific memory locations.

Question 11

What is the purpose of return 0 in main()?

Answer 11

It indicates successful program execution. A return value of 0 typically means the program ran without errors.

Question 12

What is a loop in C?

Answer 12

A loop is a control structure used to repeat a block of code multiple times. Common loops in C are for, while, and do-while loops.

Question 13

What are conditional statements in C?

Answer 13

Conditional statements like if, else, and switch are used to execute different blocks of code based on whether a condition is true or false.

Question 14

What is a function in C?

Answer 14

A function is a reusable block of code designed to perform a specific task. It is defined with a return type, function name, and parameters.

Question 15

What is the difference between call by value and call by reference in C?

Answer 15

Call by value:
A copy of the variable’s value is passed to the function, and changes made within the function do not affect the original variable.

Call by reference:
A reference (memory address) is passed to the function, allowing changes made within the function to affect the original variable.

Question 16

What are arrays in C?

Answer 16

Arrays are a collection of elements of the same data type stored in contiguous memory locations, accessed using an index.

Question 17

What is procedural programming?

Answer 17

Procedural programming is a paradigm that organizes code into procedures or functions. C is a procedural language, meaning it follows a step-by-step approach for task execution.

Question 18

What are the key differences between C and Java?

Answer 18

C is procedural, and Java is object-oriented.
C gives more control over system resources, but Java handles memory management automatically with garbage collection.
Java uses a virtual machine (JVM) for portability, while C compiles to machine code that is hardware-specific.

Question 19

What are the stages of the C compilation process?

Answer 19

Preprocessing: Handles directives like #include.
Compilation: Translates source code into object code.
Linking: Combines object code and libraries to create an executable.
Execution: The final executable runs on the system.

Question 20

What are preprocessor directives in C?

Answer 20

Preprocessor directives are instructions processed before compilation, such as #include for including files, and #define for defining constants.

Question 21

Write a basic “Hello World” program in C.

Answer 21

include <stdio.h></stdio.h>

int main() {
printf(“Hello World!\n”);
return 0;
}

Question 22

How does memory management differ between C and Java?

Answer 22

In C, memory is managed manually using functions like malloc and free, whereas Java automatically handles memory using garbage collection.

Question 23

What is stream-based I/O in C?

Answer 23

C provides functions like printf and scanf for stream-based input and output, handling data as a continuous flow.

Question 24

What does EXIT_SUCCESS in C indicate?

Answer 24

EXIT_SUCCESS is a macro defined in stdlib.h that indicates the program terminated successfully.

Question 25

What does EXIT_FAILURE in C indicate?

Answer 25

EXIT_FAILURE is a macro defined in stdlib.h that indicates the program failed or encountered an error.

Question 26

Why should EXIT_SUCCESS and EXIT_FAILURE be used instead of returning integer values directly?

Answer 26

Using EXIT_SUCCESS and EXIT_FAILURE ensures that your program is portable, readable, and compliant with the C/C++ standards. It’s a better approach than using raw integer values.