Convert hex number to integer : hexadecimal « Data Types « C++ Tutorial

1. C++ Tutorial
2. Data Types
3. hexadecimal

#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;

long hex2int(const string& hexStr);

int main( ) {
  string str1 = "0x12AB";
  cout << hex2int(str1) << endl;
  string str2 = "12AB";
  cout << hex2int(str2) << endl;
}


long hex2int(const string& hexStr) {
  char *offset;

  if (hexStr.length( ) > 2) {
    if (hexStr[0] == '0' && hexStr[1] == 'x') {
      return strtol(hexStr.c_str( ), &offset, 0);
    }else{
      cout << "hex must start with 0x";
      return 0;
    }
  }
}

4779
hex must start with 0x0