C Programming Chapter 2

Questions and Answers

What does the strlen function return?

The total size of the memory allocated for the string including the null character.

The number of characters in the string including the null character.

The number of characters in the string excluding the null character. (correct)

The number of bytes allocated for the entire string including the null character.

What happens if the new operator fails to allocate memory?

It returns a NULL pointer. (correct)

It returns an integer indicating the type of error.

It returns a pointer to the allocated memory.

It throws an exception.

Which task does the strcpy function perform?

Copies only the non-null characters from the source string.

Copies characters up to the last non-null character.

Copies the source string to the destination, including the null character. (correct)

Copies the source string to the destination, excluding the null character.

In pointer arithmetic, adding an integer to a pointer does what?

Increases the pointer based on the size of the data type it points to. Signup and view all the answers

Why is it important to manage dynamic memory allocation carefully?

To avoid memory leaks and exhaustion of memory resources. Signup and view all the answers

What is the expected outcome after using the strlen function on an empty string?

0, since there are no characters before the null character. Signup and view all the answers

If a programmer tries to copy more characters than allocated in the destination string with strcpy, what is likely to happen?

It will overwrite memory beyond the allocated space, potentially causing a crash. Signup and view all the answers

If an int is represented by 4 bytes, what does adding 1 to an int pointer do?

Moves the pointer to the next int value, increasing the address by 4 bytes. Signup and view all the answers

What is the correct way to dynamically allocate an array of characters to hold a string of length n using C++?

char* arr = new char[n]; Signup and view all the answers

What is pointer arithmetic often used for in programming?

To iterate through arrays or other data structures. Signup and view all the answers

Study Notes

Pointers

A pointer is an address of a memory location, allowing indirect access to data.
Pointer variables need to be defined for specific data types, e.g., int *ptr1; for integers and char *ptr2; for characters.
The value of a pointer variable is the address of the variable it points to, such as ptr1 = &num;, where num is an integer variable.
The address operator & retrieves the memory address of a variable, while the dereference operator * accesses the contents at that address, e.g., *ptr1 retrieves the value of num.
Pointer types must match the type of the data they point to, except for void*, which can point to any data type.
Pointers can be cast to different types, such as converting an int* to a char* via (char*) ptr1.

Null Pointers

The null pointer (value 0) is used for initializing pointers and marking the end of pointer-based structures like linked lists.

Dynamic Memory

The heap is used for dynamically allocating memory during program execution, in contrast to the program stack which is static.
The new operator allocates memory on the heap for a specified type and returns a pointer to it, e.g., int *ptr = new int;.
Memory allocated on the heap persists beyond the scope of the function that created it and must be manually released using the delete operator.
Functions like strlen and strcpy handle string operations; strlen counts characters up to the null terminator while strcpy copies strings including the null character.
Dynamic memory can become exhausted if not managed properly, leading new to return 0 when it fails to allocate.

Pointer Arithmetic

Pointer arithmetic allows adding or subtracting integers to/from pointers, affecting the pointer based on the size of the data type pointed to.
For example, adding 1 to an integer pointer shifts the pointer by the size of an integer (e.g., 4 bytes).

Description

Explore the concepts of pointers in C programming with this quiz. Learn how pointers work, how to define them, and their significance in data access. Test your understanding of pointer variables and their types.