I taught first-semester C for several years, and still got a couple of these wrong - although, to be honest, the way we taught the class at my alma mater we ste

I taught first-semester C for several years, and still got a couple of these wrong - although, to be honest, the way we taught the class at my alma mater we steered well clear of these situations. We told students that C perform type promotions and automatic conversions, but either had them use a uniform type to begin with - int typically - or told them to convert explicitly and avoid Still, the most important suggestion I would make here is: Always compile with warnings enabled, in particular: * -Wstrict-overflow=1 and maybe even -Wstrict-overflow=3 * -Wsign-compare * -Wsign-conversion * -Wfloat-conversion * -Wconversion * -Wshift-negative-value (or just `-Wall -Wextra`) And maybe also: * -fsanitize=signed-integer-overflow * -fsanitize=float-cast-overflow (These are GCC flags, should work for clang as well.)