What is numeric promotion?

Question

Can any one tell what is numeric promotion?

Answer 1

Numeric promotion is a conversion of an operand (at least one of the numbers involved) to a common type.

For example:

int i = 10;
double d1 = 2.5;
double d2 = d1 * i;

In this case, i is promoted to double so the calculation can be performed. In some ways, you can think of this is analogous to boxing, but boxing involves moving from a struct to an object (from the stack to the heap). But, using the analogy does give an idea of the fact the integral value is being made into a floating point to perform the calculation.