0x0A-argc_argv

0x0A. C - argc, argv

• By Julien Barbier

Resources

Read or watch:

• Arguments to main
• argc and argv
• What does argc and argv mean?
• how to compile with unused variables

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

• How to use arguments passed to your program
• What are two prototypes of main that you know of, and in which case do you use one or the other
• How to use __attribute__((unused)) or (void) to compile functions with unused variables or parameters

Requirements

General

• Allowed editors: vi, vim, emacs
• All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
• All your files should end with a new line
• A README.md file, at the root of the folder of the project is mandatory
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• You are not allowed to use global variables
• No more than 5 functions per file
• The prototypes of all your functions and the prototype of the function _putchar should be included in your header file called main.h
• Don't forget to push your header file
• You are allowed to use the standard library

Tasks

---

0. It ain't what they call you, it's what you answer to

mandatory

Write a program that prints its name, followed by a new line.

-   If you rename the program, it will print the new name, without having to compile it again

-   You should not remove the path before the name of the program

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 0-whatsmyname.c -o mynameis

julien@ubuntu:~/0x0A. argc, argv$ ./mynameis

./mynameis

julien@ubuntu:~/0x0A. argc, argv$ mv mynameis mynewnameis

julien@ubuntu:~/0x0A. argc, argv$ ./mynewnameis

./mynewnameis

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming -   Directory: 0x0A-argc_argv -   File: 0-whatsmyname.c

1. Silence is argument carried out by other means

mandatory

Write a program that prints the number of arguments passed into it.

-   Your program should print a number, followed by a new line

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 1-args.c -o nargs

julien@ubuntu:~/0x0A. argc, argv$ ./nargs

0

julien@ubuntu:~/0x0A. argc, argv$ ./nargs hello

1

julien@ubuntu:~/0x0A. argc, argv$ ./nargs "hello, world"

1

julien@ubuntu:~/0x0A. argc, argv$ ./nargs hello, world

2

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming

-   Directory: 0x0A-argc_argv

-   File: 1-args.c

2. The best argument against democracy is a five-minute conversation with the average voter

mandatory

Write a program that prints all arguments it receives.

-   All arguments should be printed, including the first one

-   Only print one argument per line, ending with a new line

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 2-args.c -o args

julien@ubuntu:~/0x0A. argc, argv$ ./args

./args

julien@ubuntu:~/0x0A. argc, argv$ ./args You can do anything, but not everything.

./args

You

can

do

anything,

but

not

everything.

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming

-   Directory: 0x0A-argc_argv

-   File: 2-args.c

3. Neither irony nor sarcasm is argument

mandatory

Write a program that multiplies two numbers.

-   Your program should print the result of the multiplication, followed by a new line

-   You can assume that the two numbers and result of the multiplication can be stored in an integer

-   If the program does not receive two arguments, your program should print Error, followed by a new line, and return 1

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 3-mul.c -o mul

julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 3

6

julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 -3

-6

julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 0

0

julien@ubuntu:~/0x0A. argc, argv$ ./mul 245 3245342

795108790

julien@ubuntu:~/0x0A. argc, argv$ ./mul

Error

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming

-   Directory: 0x0A-argc_argv

-   File: 3-mul.c

4. To infinity and beyond

mandatory

Write a program that adds positive numbers.

-   Print the result, followed by a new line

-   If no number is passed to the program, print 0, followed by a new line

-   If one of the number contains symbols that are not digits, print Error, followed by a new line, and return 1

-   You can assume that numbers and the addition of all the numbers can be stored in an int

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 4-add.c -o add

julien@ubuntu:~/0x0A. argc, argv$ ./add 1 1

2

julien@ubuntu:~/0x0A. argc, argv$ ./add 1 10 100 1000

1111

julien@ubuntu:~/0x0A. argc, argv$ ./add 1 2 3 e 4 5

Error

julien@ubuntu:~/0x0A. argc, argv$ ./add

0

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming

-   Directory: 0x0A-argc_argv

-   File: 4-add.c

5. Minimal Number of Coins for Change

#advanced

Write a program that prints the minimum number of coins to make change for an amount of money.

-   Usage: ./change cents

-   where cents is the amount of cents you need to give back

-   if the number of arguments passed to your program is not exactly 1, print Error, followed by a new line, and return 1

-   you should use atoi to parse the parameter passed to your program

-   If the number passed as the argument is negative, print 0, followed by a new line

-   You can use an unlimited number of coins of values 25, 10, 5, 2, and 1 cent

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 100-change.c -o change

julien@ubuntu:~/0x0A. argc, argv$ ./change

Error

julien@ubuntu:~/0x0A. argc, argv$ ./change 10

1

julien@ubuntu:~/0x0A. argc, argv$ ./change 100

4

julien@ubuntu:~/0x0A. argc, argv$ ./change 101

5

julien@ubuntu:~/0x0A. argc, argv$ ./change 13

3

julien@ubuntu:~/0x0A. argc, argv$

Repo:

-   GitHub repository: alx-low_level_programming

-   Directory: 0x0A-argc_argv

-   File: 100-change.c