How to make the division of 2 ints produce a float instead of another int?

Question

In another Bruce Eckels exercise in calculating velocity, v = s / t where s and t are integers. How do I make it so the division cranks out a float?

Answer 1

Just cast one of the two operands to a float first.

v = (float)s / t;

The cast has higher precedence than the division, so happens before the division.

The other operand will be effectively automatically cast to a float by the compiler because the rules say that if either operand is of floating point type then the operation will be a floating point operation, even if the other operand is integral. Java Language Specification, §4.2.4 and §15.17