Declaring an entity to be const tells the compiler to make it "read-only."

Because it cannot be assigned to, a const object must be properly initialized when it is first declared.

For example:

   const int x = 33;
   const int v[] = {3, 6, x, 2 * x};   // a const array

Working with the preceding declarations:

 ++x ;           // error
 v[2] = 44;      // error

No storage needs to be allocated for a const initialized with an int or some other simple type unless its address is taken.

use const entities instead of embedding numeric literals (sometimes called "magic numbers") in your code.

For example, instead of writing something like this:

for(i = 0; i < 327; ++i) {
   ...
}

use something like this:

// const declaration section of your code
const int SIZE = 327;
...
for(i = 0; i < SIZE; ++i) {
    ...
}