Question on C code

PART 2: 1. Assume vdisk is a VIRTUAL disk. Write C code to open it for READ: Then read MBR of vdisk into char buf[512]: 2. Assume: struct partition *p; char buf[512] contains a disk MBR, which has 4 partitions, pl to P4. Write C code to let p point at P2 in buf[ ]: Then print P2's start_sector: 3. For int *p, how many bytes is *p? putchar(char c) prints (1-byte) char. How does putchar(*ip) work