Strings, integers, and hex oh my!

[Kraig K]

I have an imbedded controller (Rabbit 2000) that is programmed in a modified form of C, but I think much of the "basics" are the same. I have to send commands to a device in hex. The following...

char *run;
run = "\x55\x03\x10";

serBputs(run); //sends data out the serial port

...starts my device. But I want to be able to vary the last value. I've tried several things, creating another string without the last value, setting an integer to say "100", converting that to a string and combining them. This works on a fundamental level, but the "100" doesn't get converted to hex, it thinks it's a string.

So what I want is:

char *run;
int i; // i can vary from 1-255

run = "\x55\x03\x(i)" // this is not legal

How can I accomplish this?