Part-1

Greatest Common Divisor: Show a recursive implementation of Euclid's algorithm for finding the greatest common divisor (GCD) of two integers. Descriptions of this algorithm are shown in algebra books and on the Web. (Note: A nonrecursive version of the GCD problem was provided in the programming exercises.) Show a test program that calls your GCD procedure five times, using the subsequent pairs of integers: (5,20), (24,18), (11,7), (432,226), (26,13). After each procedure call, display the GCD.

Part-2

. Str_concat Procedure

Write a procedure named Str_concat that concatenates a source string to the end of a target string. Sufficient space must exist in the target string to accommodate the new characters. Pass pointers to the target and source strings. Here is a sample call:

.data

targetStr BYTE "ABCDE",10 DUP(0)

sourceStr BYTE "FGH",0

.code

INVOKE Str_concat, ADDR targetStr, ADDR sourceStr

Part-3

mWritestringAttr Macro

Prepare a macro that writes a null-terminated string to the console with a given text color. The macro parameters could include the string name and the color. Hint: Call SetTextColor from the book's link library. Write a program that tests your macro with various strings in different colors. Sample call:

.data

myStringdb "Here is my string",0

.code

mWritestringmyString, white

File Allocation Table (FAT) The FAT12, FAT16, and FAT32 file systems use a table called the file allocation table (FAT) to keep track of each file's location on the disk. The FAT maps the disk clusters, showing their ownership by specific files. Each entry corresponds to a cluster number, and each cluster contains one or more sectors. In other words, the 10th FAT entry identifies the 10th cluster on the disk, the 11th entry identifies the 11th cluster, and so on. Each file is represented in the FAT as a linked list, called a cluster chain . Each FAT entry contains an integer that identifies the next entry. Two cluster chains are shown in Figure 15-14, one for File1 and the other for File2 . File1 occupies clusters 1, 2, 3, 4, 8, 9, and 10. File2 occupies clusters 5, 6, 7, 11, and 12. The eoc( end of chain ) marker in the last FAT entry for a file is a predefined integer value marking the final cluster in the chain.

When a file is created, the operating system looks for the first available cluster entry in the FAT. Gaps occur when not enough contiguous clusters are available to hold the entire file. In the preceding diagram, this happened to both File1 and File2 . When a file is modified and saved back to disk, its cluster chain often becomes increasingly fragmented. If many files become fragmented, the disk's performance begins to degrade because the read/write heads must jump between different tracks to locate all of a file's clusters. Most operating systems supply a built-in disk defragmentation utility. Figure 15-14 Example: Two Cluster Chains. File1: starting cluster number 1, size 7 clusters 2348 12 9 10 eoc 3456 7 8 File2: starting cluster number 5, size 9 10 1112 13 14 15 16 5 clusters 6711 12 3456 7 8 15.3.4 Section Review 12 eoc 9 10 1112 13 14 15 16

Part-4

String Input/Output

Write a program that inputs the subsequent information from the user, using the Win32 ReadConsole function: first name, last name, age, phone number. Display the same information with labels and attractive formatting, using the Win32 WriteConsole function. Do not use any procedures from the Irvine32 library.