Unit Converter (CS50R Final Project)

A lightweight R package for converting between common units of temperature, length, and weight. Designed for clarity, ease of use, and reliability — with unit tests and full documentation.

Final project for CS50’s Introduction to Programming with R.

---

Functions Provided

Function	Description	Example
C_to_F()	Convert Celsius to Fahrenheit	C_to_F(0) → 32 °F
F_to_C()	Convert Fahrenheit to Celsius	F_to_C(32) → 0 °C
kg_to_lbs()	Convert kilograms to pounds	kg_to_lbs(1) → 2.2 lbs
lbs_to_kg()	Convert pounds to kilograms	lbs_to_kg(2.20462) → 1 kg
cm_to_inches()	Convert centimetres to inches	cm_to_inches(2.54) → 1 inch
inches_to_cm()	Convert inches to centimetres	inches_to_cm(1) → 2.54 cm

Each function checks for:

• Missing or null inputs
• Non-numeric inputs
• Precision rounding

---

Testing

Unit tests are provided using the testthat framework. Run all tests using:

devtools::test()

Test coverage includes:

• Correct conversions
• Handling of NA/missing/null inputs
• Type safety (e.g., strings, lists)

---

Project Structure

unitconverter/
├── R/                   # Source functions (e.g., C_to_F.R)
├── man/                 # Manual .Rd documentation files
├── tests/
│   ├── testthat.R       # Load test suite
│   └── testthat/        # Unit tests per function
├── NAMESPACE            # Export definitions
└── README.md            # This file

---

How to Use

You can load the functions into your R session as follows:

source("R/C_to_F.R")
C_to_F(25)  # Output: 77 °F

Or if packaging via devtools:

library(devtools)
load_all("unitconverter")
kg_to_lbs(70)

---

Example Output

> C_to_F(100)
[1] "212 °F"

> cm_to_inches(10)
[1] "3.94 inches"

> lbs_to_kg(220)
[1] "99.79 kg"

---

What I Learned

• How to write modular, reusable R functions
• Robust input validation and error handling
• Documenting with .Rd files
• Testing using testthat
• Building a basic R package structure

---

License

MIT

---