Const In C Language

In C, the const keyword is used to create a read-only variable, which means that its value cannot be modified after it has been initialized. A variable that is declared as const must be initialized when it is defined, and its value cannot be changed later.

Here is an example of how to declare a variable as const:

Copy code

const int pi = 3.14;

The const keyword can also be used with pointers and arrays. For example, you can create a pointer to a constant variable, which means that the pointer can be used to access the variable, but the value of the variable cannot be modified through the pointer.

Copy code

int num = 10; const int *ptr = # // pointer to a constant integer

It's important to keep in mind that when you declare a pointer to a constant variable, you cannot use the pointer to modify the value of the variable, but you can use it to access the value of the variable. If you try to use the pointer to modify the value of the variable, the program will generate a compile-time error.

Additionally, you can also create a constant pointer that points to a variable. This means that the pointer cannot be reassigned to point to a different variable, but the value of the variable that the pointer points to can still be modified.

Copy code

int num = 10; int * const ptr = # // constant pointer to an integer

Using the const keyword in C allows the programmer to prevent accidental modification of data, which can help to prevent bugs and ensure that the program behaves as expected.