Usual arithmetic conversions in C : Whats the rationale behind this particular rule

Question

From k&R C

• First, if either operand is long double, the other is converted to long double.
• Otherwise, if either o

Answer 1

Do these conversions happen if a, b and c were short ?

Yes, integer promotions are done on all small integer types: char, short and C99 bool.

Strictly speaking, a C program cannot perform any form of arithmetic on anything smaller than an int, unless the compiler optimizes away the integer promotions.