combining digits into a number

Hi,

im getting digits from a file, but i need to know how to combine these digits into a number so i can store it as an int. So for example my file is

1234

i then read digit by digit like so..

current1 = fgetc( inFile ); /* =1 */

current2= fgetc( inFile ); /* =2 */

current3 = fgetc( inFile ); /* =3 */

current4 = fgetc( inFile ); /* =4 */

now how do i form these into a single number again.. is it something like..

int finalnum = current1 +current2 +current3 +current4 + something..;

im not sure.. please help

thanks.