Conversion of datatypes (probably not what you think :p)

[deadeyes]

Hi all,

I have the following problem in C++:
I have a string with the following contents. I cannot change this because this is incoming data from a library (libpcap).
String t = "\x00\x81"; // this is the value I get from pcap

I want to convert this hexadecimal to it's decimal value (not as ascii value).
So eventually I should have:
int i = 129; // 192 is the value of 81 in hex (00 is just 0)

How can I do this?
I tried alot but always seem to get stuck :s

Help will be very appreciated!

[weaknessforcats]

1) Locate the x.
2) the next char is the left most byte. Save it in a char array.
3) the next char is the next byte. Save as the next byte in the char array.
4) continue saving until you reach the \
5) the number of saves the is hex base value (a power of 16) of the first array element and your number is in the array.

Go from there. Be sure to subtract 48 from the array char values to get the corresponding int value. Multiply by the the hex base value for that position and accumulate the result in an int.

[deadeyes]

How can I locate the x? the \x gives a sign that it is a hex value.
So \x00 is just 1 character :s

[weaknessforcats]

I'm sorry I didn't pick up on the \x.

This constant:

"\x00\x81"

uses the escape character \ followed by an x. There is no \x escape code. Results are indeterminate. A C++ string has a size() of 0 when initialized to this. printf(), also displays garbage.

What is the value you are getting exactly??

Usually hex values are preceded by 0x.