Negative ASCII value

Question

What\'s the point of negative ASCII values?

int a = \'«\'; //a = -85 but as in ASCII table \'<<\' should be 174

Answer 1

This is an artefact of your compiler's char type being a signed integer type, and int being a wider signed integer type, and thus the character constant is considered a negative number and is sign-extended to the wider integer type.

There is not much sense in it, it just happens. The C standard allows for compiler implementations to choose whether they consider char to be signed or unsigned. Some compilers even have compile time switches to change the default. If you want to make sure about the signedness of the char type, explicitly write signed char or unsigned char, respectively.

Use an unsigned char to be extended to an int to avoid the negative int value, or open a whole new Pandora's box and enjoy wchar.