Question $1$

Create a C program $("$collatz$\_$sequence.c$")$ that generates a collatz sequence for a given initial start number. The

Collatz conjecture concerns what happens when we take any positive integer $n$ and apply the following algorithm:

$n=2n,ifnis$ even

$n=3n+1n=3n+1,ifnis$ odd

The conjecture states that when this algorithm is continually applied, all positive integers will eventually reach $1.$

For example, if $n=35,$ the sequence is $35,106,53,160,80,40,20,10,5,16,8,4,2,1.$

The program will use parent and child processes to create this sequence. The parent process will read a list of

starting numbers from the file "start$\_$numbers.txt$"$ and store them in an array. For each number, the parent will

create a collatz sequence and create a shared$-$memory object between the parent and child processes to pass the

sequence to the child. The child will open the shared$-$memory object, output$/$print the sequence, and complete

itself. Because the memory is shared, any changes the parent makes will also be reflected in the child process.

The parent process will progress through the following steps for each number read from the "start$\_$numbers.txt$"$

file:

a$.$ Establish the shared$-$memory object $($shm$\_$open$(),$ ftruncate$(),$ and mmap$()).$

b$.$ Create a collatz sequence for the read number.

c$.$ Save the sequence to a shared$-$memory object.

d$.$ Create the child process and wait for it to terminate.

The parent will spawn multiple child processes $($equal to the start numbers provided in the "start$\_$numbers.txt$")$

and pass different collatz sequence numbers to each child.

The child will progress through the following steps:

a$.$ Establish the shared$-$memory object $($shm$\_$open$(),$ ftruncate$(),$ and mmap$()).$

b$.$ Output the contents of shared memory.

c$.$ Remove the shared$-$memory object.

The program exits when all sequences equal to start$\_$numbers are printed on the console.

Use makefile to compile the program written above. The instructions to use and contents of the makefile have

been provided on the MyLS course page. The other implementation details are at your discretion, and you are free

to explore.

To invoke the program, use the command: $./$collatz$\_$sequence start$\_$numbers.txt in the terminal OR use the

command: make runq$1$ via makefile.

The expected output for Question $2$:

$ make runq$1$

$./$collatz$\_$sequence start$\_$numbers.txt

Parent Process: The positive integer read from file is $10$

Child Process: The generated collatz sequence is $105168421$

Parent Process: The positive integer read from file is $53$

Child Process: The generated collatz sequence is $53160804020105168421$

Parent Process: The positive integer read from file is $99$

Child Process: The generated collatz sequence is $992981494482241125628147221134175226134020105168421$

Note: When submitting the source code files for Question $1,$ name them like:

$$ collatz$\_$sequence.c

# Makefile for collatz$\_$sequence.c

# Compiler

CC $=$ gcc

# Compiler Flags

CFLAGS $=-$Wall $-$Wextra $-$std$=$c$99$

# Executable Name

TARGET $=$ collatz$\_$sequence

# Source Files

SRC $=$ collatz$\_$sequence.c

# Default Target

all: $$($TARGET$)$

# Build the target executable

$$($TARGET$)$: $$($SRC$)$

$$($CC$)$ $$($CFLAGS$)-$o $$($TARGET$)$ $$($SRC$)-$lrt

# Clean up build files

clean:

rm $-$f $$($TARGET$)*.$o

# Run the program

run:

$./$$$($TARGET$)$ start$\_$numbers.txt

# Phony targets

$.$PHONY: all clean run