How to merge bytes

My issue:

local byte1 = 255 --//11111111
local byte2 = 255 --//11111111
local byte3 = 255 --//11111111
local byte4 = 255 --//11111111
local merged = -//does something with byte1, byte2, byte3, and byte4 in order to merge them together and get 11111111111111111111111111111111 which is 4294967295

What I want to do is basically put 4 bytes together sequentially to get a 4-byte number. I need this to rewrite a security algorithm I once wrote in c# or some other cstyle language.
Like this: (note that this code is horrible and won't work at all but it has the general idea.

#include "stdafx.h"
#include <iostream>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
	char x = 0;	  
	char * x1 = &amp;x;
	char * x2 = (&amp;x + 1);
	char * x3 = (&amp;x + 2);
	char * x4 = (&amp;x + 3);
	*x1 = 255;
	*x2 = 255;
	*x3 = 255;
	*x4 = 255;
	int * result = (int *) &amp;x;
	cout << *result;
	return 0;
}

Obviously if you run the above on a computer, it'll corrupt the stack and blah blah blah. Basically

x1 = 0b11111111 #255
x2 = 0b11111111 #255
x3 = 0b11111111 #255
x4 = 0b11111111 #255
x5 = 0b11111111111111111111111111111111 #Big number

Basically making a 4-byte integer if you have the bytes you want it to be made of, in lua.

Split into new topic.

Well, you could or them together at various amounts of left shift.

local bytes={1,2,3,4}
local dword=0
for i=1,4 do
  dword=dword+bytes[i]*256^(i-1)
end
print(string.format("%x",dword)) --outputs "4030201"

alternately, with bit api,

local bytes={1,2,3,4}
local dword=0
for i=1,4 do
  dword=bit.bor(dword,bit.blshift(bytes[i],(i-1)*8))
end
print(string.format("%x",dword)) --outputs "4030201"