Float compile-time calculation not happening?

Question

A little test program:

#include 


const float TEST_FLOAT = 1/60;

const float TEST_A = 1;
const float TEST_B = 60;
const float TEST_C = TEST_A /         


        

Answer 1

In

1/60

Both of the operands are integers, so integer arithmetic is performed. To perform floating point arithmetic, at least one of the operands needs to have a floating point type. For example, any of the following would perform floating point division:

1.0/60
1.0/60.0
1/60.0

(You might choose to use 1.0f instead, to avoid any precision reduction warnings; 1.0 has type double, while 1.0f has type float)

Shouldn't TEST_FLOAT have the same value than TEST_C?

In the TEST_FLOAT case, integer division is performed and then the result of the integer division is converted to float in the assignment.

In the TEST_C case, the integer literals 1 and 60 are converted to float when they are assigned to TEST_A and TEST_B; then floating-point division is performed on those floats and the result is assigned to TEST_C.

Is TEST_C value resolved at compile time or at runtime?

It depends on the compiler; either method would be standards-conforming.