array in C

Question

is it fine to not use all the index in an array
like
char name[30];
scanf("%s", name);
\*lets say that the user enters characters that are less than 20, is it fine to declare an array with an unused indexes?*\

Answer 1

Of course, you can, by specifying the size of the array when declaring a variable, you thereby reserve the amount of memory and no more, so the less you reserve, the less your program will consume RAM.