You can do this by yourself:
unsigned char a = (unsigned char)'\xa3'; //163
char data[4];
int value, pos = 0;
for (int i = 100; i > 0; i /= 10)
{
value = a / i;
a -= i * value;
data[pos++] = value + 48;
}
data[pos] = '\0';
This is very simple C code. If you do not understand this, you should take your C book and try to explore every bit of this. Just to copy the code will teach you nothing.