Question: If I want to Develop SSIS Package from scratch what techniques/needs to be fallow in related to design,development,testing and deployment.

Answer: 
Use the `%x` format in [sscanf](http://www.cplusplus.com/reference/clibrary/cstdio/sscanf/)!
The C++ way of doing it, with streams:

```
#include <iomanip>
#include <iostream>
#include <sstream>

int main() {
    std::string hexvalue = "FF";
    int value;
    // Construct an input stringstream, initialized with hexvalue
    std::istringstream iss(hexvalue);
    // Set the stream in hex mode, then read the value, with error handling
    if (iss >> std::hex >> value) std::cout << value << std::endl;
    else std::cout << "Conversion failed" << std::endl;
}

```

The program prints 255.