C pointers can be quite confusing, especially for beginners or those coming from higher-level programming languages like Python or JavaScript. In this blog post, we will introduce pointers in a simplified yet comprehensive manner.
What is a Pointer?
A pointer is essentially the address of a block of memory that contains a variable. To understand this better, let’s consider an example. When we declare an integer variable like so:
int age = 37;
We can use the & operator to obtain the memory address of the variable:
printf("%p", &age); // 0x7ffeef7dcb9c
The %p format specified in the printf() function allows us to print the address value.
We can also assign the address to a variable:
int *address = &age;
By using int *address in the declaration, we are actually creating a pointer to an integer.
Accessing the Value of a Variable Using Pointers
To obtain the value of the variable that an address points to, we use the pointer operator *. Consider the following code:
int age = 37;
int *address = &age;
printf("%u", *address); // 37
Here, we are using the pointer operator to retrieve the value of the variable that the address is pointing to. Note that in this case, we are not declaring a new variable; instead, we are simply accessing the value.
Pointers and Arrays
Pointers are extremely useful when working with arrays. When we declare an array like this:
int prices[3] = { 5, 4, 3 };
The prices variable is essentially a pointer to the first element of the array. To retrieve the value of the first element, we can use the printf() function:
printf("%u", *prices); // 5
What’s even more interesting is that we can access the subsequent elements by incrementing the pointer:
printf("%u", *(prices + 1)); // 4
This technique can be applied to access all the other values in the array.
More Applications of Pointers
Apart from arrays, pointers have numerous other applications. For example, when dealing with strings, which are essentially arrays under the hood, we can perform various string manipulation operations using pointers. Additionally, pointers allow us to pass the reference of an object or a function around, eliminating the need for unnecessary resource consumption during copying.
It is essential to familiarize yourself with pointers, as many important concepts in C are built upon this foundational concept. Make sure to run the above examples to gain a better understanding of how pointers work in practice.
Tags: C programming, pointers, arrays, memory management