anversa-pro / holbertonschool-low_level_programming

Low-Level projects in C to develop logic, memory usage understanding, and data structures and manipulation.

0x00 C - Hello, World

Learning Objectives

• Why C programming is awesome
• Who invented C
• Who are Dennis Ritchie, Brian Kernighan and Linus Torvalds
• What happens when you type gcc main.c
• What is an entry point
• What is main
• How to print text using printf, puts and putchar
• How to get the size of a specific type using the unary operator sizeof
• How to compile using gcc
• What is the default program name when compiling with gcc
• What is the official Holberton C coding style and how to check your code with betty-style
• How to find the right header to include in your source code when using a standard library function
• How does the main function influence the return value of the program

Shell Scripts

• Allowed editors: vi, vim, emacs
• All your scripts will be tested on Ubuntu 20.04 LTS
• All your scripts should be exactly two lines long ($ wc -l file should print 2)
• All your files should end with a new line
• The first line of all your files should be exactly #!/bin/bash

Betty linter

To run the Betty linter just with command betty <filename>:

• Go to the Betty repository https://github.com/holbertonschool/Betty
• Clone the repo to your local machine
• cd into the Betty directory
• Install the linter with sudo ./install.sh
• emacs or vi a new file called betty, and copy the script below:

` #!/bin/bash # Simply a wrapper script to keep you from having to use betty-style # and betty-doc separately on every item. # Originally by Tim Britton (@wintermanc3r),multiargument added by # Larry Madeo (@hillmonkey)

  BIN_PATH="/usr/local/bin"
  BETTY_STYLE="betty-style"
  BETTY_DOC="betty-doc"

  if [ "$#" = "0" ]; then
     echo "No arguments passed."
     exit 1
  fi

  for argument in "$@" ; do
  echo -e "\n========== $argument =========="
  \${BIN_PATH}/${BETTY_STYLE} "$argument"
  \${BIN_PATH}/${BETTY_DOC} "$argument"
  done`

• Once saved, exit file and change permissions to apply to all users with chmod a+x betty.
• Move the betty file into /bin/ directory or somewhere else in your $PATH with sudo mv betty /bin/
• You can now type betty <filename to run the Betty linter!

0x01. VARIABLES, IF, ELSE, WHILE

Learning Objectives

• What are the arithmetic operators and how to use them
• What are the logical operators (sometimes called boolean operators) and how to use them
• What the the relational operators and how to use them
• What values are considered TRUE and FALSE in C
• What are the boolean operators and how to use them
• How to use the if, if ... else statements
• How to use comments
• How to declare variables of types char, int, unsigned int
• How to assign values to variables
• How to print the values of variables of type char, int, unsigned int with printf
• How to use the while loop
• How to use variables with the while loop
• How to print variables using printf
• What is the ASCII character set
• What are the purpose of the gcc flags -m32 and -m64

0x02 FUNCTIONS, NESTED LOOPS

Learning Objectives

• What are nested loops and how to use them
• What is a function and how do you use functions
• What is the difference between a declaration and a definition of a function
• What is a prototype
• Scope of variables
• What are the gcc flags -Wall -Werror -pedantic -Wextra -std=gnu89
• What are header files and how to to use them with #include

0x03 DEBUGGING

Learning objectives

• What is debugging
• What are some methods of debugging manually
• How to read the error messages

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