About Manipulating Binary File

myFile.txt is a binary file:

Followed is the result of od -Ax -tx1 myFile.txt:
000000 68 01 00 00 a0 05 00 00 48 00 00 00 38 05 00 00
000010 53 01 00 00 01 00 00 00 00 00 00 00 00 00 00 00

Followed is the code
//myFile.txt is being memory map
            char * mf=mmap(0,n,PROT_READ,MAP_PRIVATE,f,0);
               int decArray=decArray[16];
            int i;
            for (i=0;i<16;i++){
                    //1. How to get the value of  mf[i], and print it on the screen, all in the format of 0x00**, eg 0x0068, 0x00a0?
                    //2. How to convert mf[i] in the decimal format and store it in the decArray?
            }