Question

This is driving me nuts because I don’t know the magic words to search for to find a solution.

I initialize:

unsigned char foo[] = {'0', 'x', '1', '1'};

unsigned char bar[] = {'\0'};

Essentially I want bar[0] to be equal to the value 0x11. How do I do that? I feel stupid and I’m pretty sure there’s a simple solution but I can’t figure it out. I tried

memcpy(&bar[0], &foo[0], 1);

But that just makes bar[0] have the value of 0x30, which is the ascii value of the ‘0’ character.

Any help/hints?

Answer 1

In case you want to convert text values to integer, that can be done via sscanf function:

char * string = "0x11";
int numeric;
sscanf(string, "%i", &numeric);
// numeric is now 0x11

Note that:

• string actually has five characters, as there is a terminating zero at the end. If you ran C-string-expecting function on unterminated array {‘0’, ‘x’, ‘1’, ‘1’} you had above, if would continue processing data past the array, which is something you definitely do not want.
• In real world use with externally-supplied data, you’d have to check for return value of sscanf to make sure it really did the conversion you wanted to do.