Float Values as an index in an Array in C++

Question

Can a float value be used as the index of an array? What will happen if an expression used as an index resulted to a float value?

Answer 1

The float value will be casted to int (it can give warning or error depending on compiler's warning level)

s1 = q[12.2]; // same as q[12]
s2 = q[12.999999]; // same as q[12]
s3 = q[12.1/6.2]; // same as q[1]

Answer 2

Yes. But it's pointless. The float value will be truncated to an integer.

(You can use std::map<float, T>, however, but most of the time you'll miss the intended values because of inaccuracy.)