C Programming: Pointers and Memory Addresses

10 Questions

What is the primary purpose of the `&` operator in C programming?

To get the memory address of a variable

What is the difference between `*ptr` and `ptr`?

*ptr gives the value pointed to by the pointer, while ptr gives the address it points to

What happens when you assign `*ptr = 20;`?

The value pointed to by the pointer ptr is changed to 20

What is the purpose of the combination of `*` and `&` operators?

To manipulate the pointers and the values they point to

What is the result of `int *ptr = &arr;`?

The pointer ptr points to the first element of the array arr

What is the purpose of the `&` operator in C?

To get the memory address of a variable

What is the main difference between a linear search and a binary search?

Binary search is used for sorted arrays, while linear search is used for unsorted arrays

What is the purpose of the `*` operator in C?

To dereference a pointer and access the value at the memory address

What is the syntax for declaring a multidimensional array in C?

type arrayName[size1][size2]...

What is the purpose of the dot operator in C?

To access a structure member

Study Notes

Pointers and Memory Addresses

The * operator is used to access the value stored at the memory address to which a pointer points.
The & operator is used to get the memory address of a variable.
The * operator is known as the dereference operator.
The & operator is known as the address-of operator.

Dereference Operator (`*`)

Used to access the value at the memory address to which a pointer points.
Example: *ptr gets the value pointed to by ptr.
Can be used to modify the value of a variable through a pointer.

Address-of Operator (`&`)

Used to get the memory address of a variable.
Example: &x gets the address of variable x.
Can be used with arrays to get the address of the first element.

Combining `*` and `&` Operators

Often used together to manipulate pointers and the values they point to.
Example: Getting the value of a variable using a pointer, and changing the value using the pointer.

Arrays

A data structure consisting of related data items of the same type.
Typically fixed in size.
Declaration syntax: type arrayName[arraySize];.
Example: int c[10];.

Working with Arrays

Accessing array elements: arrayName[index].
Passing arrays to functions: specify the array name without an index.
Example: void modifyArray(int b[], int size);.

Array Operations

Sorting arrays: Bubble sort is a common algorithm.
Searching arrays: Linear search and Binary search are two common approaches.

Multidimensional Arrays

Declaration syntax: type arrayName[size1][size2]...[sizeN];.
Example: int b[2][3];.

Variable-Length Arrays

Arrays where the length is determined at runtime.
Supported in C99 and later versions.

Structures

A collection of related variables under one name.
Useful for creating records with different data types.
Declaration syntax: struct card { char *face; char *suit; };.

Working with Structures

Initializing structures: struct card oneCard = { "Three", "Hearts" };.
Accessing members of structures: Use the dot operator.
Structures can contain members that are pointers to the same structure type.