Question

Say I have a string like:

string hex = "48656c6c6f";

Where every two characters correspond to the hex representation of their ASCII, value, eg:

0x48 0x65 0x6c 0x6c 0x6f = "Hello"

So how can I get "hello" from "48656c6c6f" without having to create a lookup ASCII table? atoi() obviously won’t work here.

Answer 1

int len = hex.length();
std::string newString;
for(int i=0; i< len; i+=2)
{
    std::string byte = hex.substr(i,2);
    char chr = (char) (int)strtol(byte.c_str(), null, 16);
    newString.push_back(chr);
}