write the code in c$,$ dont chat gpt

For this question, create a folder q$3$ which should contain the following files:

$1.$ date.c: Contains a simple implementation of the date command. This

program should print the current date in at least three different formats. The

user can pass options$/$flags to specify the desired format $($e$.$g$.,-$u for UTC, $-$r

for RFC $2822$ format$).$ If no flag is passed, it should print the default date and

time format.

$2.$ cal.c: Contains a simple implementation of the cal command using Zeller's

congruence. The program should take month and year as arguments and

calculate the first day of the month using the formula for the Gregorian

calendar. If the month and year are not provided, it should print an error

message. Use Zeller$$s congruence to determine the first day of the given

month and construct the rest of the month.

$3.$ uptime.c: Contains a simple implementation of the uptime command. This

program should print the system's uptime using the sysinfo$()$ function. If no

additional options are provided, print the uptime in hours, minutes, and

seconds. Add an error message if there are any issues retrieving the uptime.

$4.$ main.c: This program will run all the executables of the above programs as

child processes using the fork$-$wait$-$exec sequence. First, create $3$ child

processes using fork. Then, inside the child processes, call one of the exec

functions to execute the above programs. Each child will run one program.

The parent process will wait for all child processes to finish before returning.

$5.$ Makefile: This makefile should build the first $3$ programs $($date$,$ cal, uptime$)$

before building the main program. Your files should be correctly compiled

using this Makefile. The output of compiling a C file should be an executable

file of the same name. For example: date.c should be compiled to date in

Linux. $[40$ pts$]$

Rubrics:

The student should have implemented the following things:

$$ Folder q$3$ containing the files date.c$,$ cal.c$,$ uptime.c$,$ main.c$,$ and

Makefile.

$$ All files should be correctly compiled without errors using make.

$$ In main.c$,$ the parent process must use fork$()3$ times, then wait$()3$

times for each of the children to finish. The children should call an exec

function on $./$date$,./$cal$,$ and $./$uptime$,$ respectively.

$$ Running the main executable should:

$$ Print the current date and time in the default format using the date

program.

$$ Display the first day of the current month calculated using Zeller's

congruence with the cal program.

$$ Show the system's uptime using the uptime program.