Type of array index in C++

Question

What is the type of array index in C++ programming language? For example in such statement:

int tab[5];

To what type 5 is converted? or may

Answer 1

In that code, 5 is just a plain integer literal, so it's just a plain int here.

§8.3.4 Arrays in n3290 (~ C++11) specifies array declarators:

In a declaration T D where D has the form

D1 [ constant-expressionopt ] attribute-specifier-seqopt

and the type of the identifier in the declaration T D1 is “derived-declarator-type-list T”, then the type of the identifier of D is an array type; if the type of the identifier of D contains the auto type-specifier, the program is ill-formed. T is called the array element type; this type shall not be a reference type, the (possibly cv-qualified) type void, a function type or an abstract class type. If the constant-expression (5.19) is present,it shall be an integral constant expression and its value shall be greater than zero.

§5.2.1 Subscripting describes what can go in the brackets in expressions:

A postfix expression followed by an expression in square brackets is a postfix expression. One of the expressions shall have the type “pointer to T” and the other shall have unscoped enumeration or integral type. The result is an lvalue of type “T.” The type “T” shall be a completely-defined object type. The expression E1[E2] is identical (by definition) to *((E1)+(E2))