Getting Started With C

This is the start of the lessons on the C programming language. C is an imperative, compiled, statically-typed, portable language.

• Imperative: we tell the computer how to accomplish a goal; we give it orders
• Compiled: the computer translates the entire code into an executable/binary code which the machine can then understand
• Statically-typed: we tell the computer exactly what type of data we want it to use instead of having it guess based on how we use the data; this makes our code run faster because time is not wasted on guessing
• Portable: we write our code and use the compiler for whichever platform/device we want to run the code on; the compiler then translates it into the machine code for that device thus saving us from having to rewrite different versions of C for different machines; we simply use different compilers

Boilerplate

Boilerplate is used to refer to the repetitive sections of code that developers have to type with little to no variation.

Examine the following C code snippet:

#include <stdio.h>

int main(void){
    // this is a comment
    printf("Hello world!\n");
    return 0;
}

Challenge

Answer the following questions:

• What would you consider to be C boilerplate?
• What is the stdio.h referring to?
• Is this header file necessary for every C program?
• What is the function printf used for?
• Why do we use the " symbol before and after Hello world!?

Grammar in C

• Keywords - these are reserved identifiers meaning that they cannot be used to mean anything else in your code than was intended by the language creator(s). Examples include #include, int and return

• Punctuations - in the same way we use punctuations as boundaries or markers in the English language, we use them in C to demarcate sections of our code:

  • single-line comments begin with //
  • multi-line comments are surrounded by /* and */
  • functions are indicated by the name of the function followed by parentheses e.g. main() and printf()
  • [ and ] are used after arrays to indicate access to the individual elements in the array
  • commas are used to separate elements in a list and semi-colons are used to end statements in C.

• Comments - these are ignored by the compiler; they are used to tell the reader the purpose of a section of code or to preserve unused code

• Literals - these are items with constant/fixed values e.g. 0,1,-7,3E+23,“Hi”

• Identifiers - these are used to identify entities in the program. They can built-in or user-defined. Identifiers must be declared before they are used. This is because C programs are executed from top to bottom. There are various kinds of identifiers:

  • data objects e.g. i and age
  • type aliases e.g. size_t
  • functions e.g. main and printf
  • constants e.g. EXIT_SUCCESS

• Functions - these are named sections of code that can be reused

• Operators - these are used to manipulate the state of a program. They can be used for initialization and assignment (=), comparison (==,<,<=,>,>=), increment (++), decrement (–), arithmetic (+,-,*,/)

Conclusion

Learning C is one of those investments that will pay dividends back to you for decades to come. Other software dev superpowers include:

• Vim motions
• Interfaces, modular design and deep classes
• Git
• Linux
• SQL
• Markdown, HTML and CSS
• Mathematical typesetting ($\LaTeX$)