How to convert byte array (containing hex values) to decimal

Question

I am writing some code for an Atmel micro-controller. I am getting some data via Uart, and I store these hex values into an array.

Suppose the elements of the array are:

Answer 1

#include 

int main(){
    char data[] = {0x1F, 0x29, 0x3C};
    int i, size = sizeof(data);
    unsigned value = 0;

    for(i=0;i