Q: What is the C programming language?
A: C is a general-purpose programming language that was developed in the early 1970s by Dennis Ritchie. It is widely used for developing system software, embedded systems, and applications.
Q: What are the key features of C language?
A: The key features of the C language include:
Simplicity and efficiency
Portability
Low-level access to memory
Structured programming constructs
Rich set of built-in functions
Extensive control flow statements
Q: What is a variable in C?
A: A variable is a named storage location in memory that can hold a value. It is used to store and manipulate data within a program. In C, variables must be declared before they are used, specifying their type.
Q: How is memory allocated for variables in C?
A: In C, memory can be allocated for variables in two ways:
Stack allocation: Variables declared inside functions are allocated memory on the stack. Memory is automatically freed when the function returns.
Heap allocation: Memory can be dynamically allocated from the heap using functions like malloc() and calloc(). The programmer is responsible for freeing the memory using free() when it is no longer needed.
Q: What is the difference between printf() and scanf() functions?
A: The printf() function is used for output, allowing you to display text and values on the screen. On the other hand, the scanf() function is used for input, allowing you to read values from the user or a file.
Q: What is the purpose of the main() function in C?
A: The main() function is the entry point of a C program. It is where the program starts execution. Every C program must have a main() function, and it typically returns an integer value indicating the exit status of the program.
Q: What is a pointer in C?
A: A pointer is a variable that holds the memory address of another variable. It allows you to indirectly access and manipulate data by referring to its memory location.
Q: How do you declare and initialize a pointer variable in C?
A: You can declare a pointer variable by specifying the data type followed by an asterisk (*). For example, int *ptr; declares a pointer to an integer. To initialize a pointer, you can assign it the address of another variable using the address-of operator (&). For example, ptr = # assigns the address of the variable num to the pointer ptr.
Q: What is the difference between malloc() and free() functions?
A: The malloc() function is used to dynamically allocate memory on the heap, while the free() function is used to deallocate the memory previously allocated by malloc() or calloc(). Failing to free dynamically allocated memory can lead to memory leaks.
Q: What is the purpose of the sizeof operator in C?
A: The sizeof operator is used to determine the size in bytes of a data type or a variable. It is often used to calculate the amount of memory required to store data or to dynamically allocate memory.
