1  Introduction to Programming

Programming is the process of designing, writing, testing, and maintaining the source code of computer programs. It involves creating a set of instructions that a computer can follow to perform specific tasks or solve problems.

1.1 What are high-level languages?

A high-level programming language is a type of programming language that provides a strong level of abstraction from the details of the computer’s hardware. These languages are designed to be easy to read, write, and understand, enabling developers to focus on problem-solving and software design rather than dealing with the complexities of the computer’s architecture.

Key features high-level languages:

  • Human-Readable Syntax

  • Portability - can usually run on multiple types of hardware

  • Built-In Libraries and Functions: High-level languages often come with extensive libraries and built-in functions that provide pre-written code for common tasks, such as handling input/output, string manipulation, and mathematical computations. This reduces the amount of code a developer needs to write from scratch.

  • Error Checking: High-level languages typically offer better error-checking mechanisms during both compile-time and runtime, which helps in catching and debugging errors more easily.

  • Examples: Python, R, Java, C++, JavaScript, Ruby

1.2 Interpreted vs compiled?

Interpreted and compiled refers to whether the sequence of instructions written by the programmer, called source code, is executed directly (by an interpreter) or whether it is first converted (by a compiler) into a sequence of machine-level primitive operations.

  • It is often easier to debug programs written in languages that are designed to be interpreted, because the interpreter can produce error messages that are easy to correlate with the source code. Compiled languages usually produce programs that run more quickly and use less space

  • Python and R are interpretable languages.

  • C, C++, Fortran are compiled languages.

1.3 What is an Integrated Development Environment (IDE)?

An IDE is a software application that provides a comprehensive set of tools to help programmers write, test, and debug their code efficiently. It combines several development tools into a single interface, making it easier to manage the various aspects of software development.

IDE features:

  • Code Editor: A text editor that supports syntax highlighting, code completion, and other features to make writing code easier.

  • Compiler/Interpreter: Tools to translate the code you write into machine code or execute it directly.

  • Debugger: A tool to help find and fix errors in your code by allowing you to step through your code, inspect variables, and understand the flow of execution.

  • Build Automation: Tools that help automate tasks like compiling the code, running tests, and packaging the software.

  • Version Control Integration: Support for version control systems like Git, allowing you to manage code changes and collaborate with others.

Examples: Spyder and R Studio

1.4 What are script files?

A script is a file containing code that is intended to be executed as a program. The code in a script typically includes instructions that perform specific tasks, such as processing data, interacting with files, automating tasks, or running web applications.

Python scripts are typically saved with a .py extension, and R scripts are saved with a .r extension.

Here is an example of a simple Python script:

# hello_world.py
print("Hello World!")
Hello World!

1.5 What is syntax?

The syntax of a language defines which strings of characters and symbols are well formed. For example, in English the string “Cat dog boy.” is not a syntactically valid sentence, because the syntax of English does not accept sentences of the form “noun noun noun”.

In Python and R, the sequence of primitives 3.2 + 3.2 is syntactically well formed, but the sequence 3.2 3.2 is not.

Examples:

result = 3.2 + 3.2   
print(result)
[1] 6.4

😃

This will produce an error:

result = 3.2 3.2   
print(result)
Error: <text>:1:14: unexpected numeric constant
1: result = 3.2 3.2
                 ^

😟

1.6 What is an algorithm?

An algorithm is simply a step-by-step set of instructions or rules designed to solve a specific problem or perform a particular task.

Example

Imagine you want to bake a cake. The recipe you follow is like an algorithm:

Step 1: Preheat the oven to 350°F.

Step 2: Mix the flour, sugar, and eggs in a bowl.

Step 3: Pour the mixture into a baking pan.

Step 4: Bake for 30 minutes.

Step 5: Let the cake cool and then serve.

In this example, the recipe gives you clear steps to follow to achieve the goal of baking a cake. Similarly, an algorithm in programming is a sequence of steps that tells the computer exactly what to do to solve a problem, like sorting a list of numbers or finding the shortest route on a map.

1.7 Reflection questions

  1. What are some everyday tasks that could be automated using programming?

  2. Why is it important to test and maintain code after it has been written?

  3. What features of an IDE do you think are most useful for new programmers, and why?

  4. How do script files make programming projects more organized and reusable?

  5. Think of a repetitive task in your daily life. Could it be turned into a script?

  6. Why is it important for programming languages to have strict syntax rules?

  7. Describe a real-life task you’ve done that followed a step-by-step process like an algorithm.