Question

Consider the C++ code below:

bool a = 5;
bool b = 6;
int c = (int)a + (int)b;

When I compile&run this code, c has the value 2. Does the standard guarantee that, in any compiler/platform, bool values initialized with false (0) or true (not necessarily 1) will be 1 in operations and the code above will always result in c being 2?

And in C99, including stdbool.h, is that still valid?

Answer 1

Section 4.7 (integer versions) of the C++ standard says:

If the source type is bool, the value false is converted to
zero and the value true is converted to one.

Section 4.9 makes the same guarantee for floating point conversions.