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README.md | 3 years ago |
README.md
macro_calculator
Instructions
Create a function calculate_macros
which receives a vector of serde_json::Value
and returns a serde_json::Value
.
The vector the function will receive will contain jsons in the following format:
{
"name": <name>,
"calories": [<value_in_kJ>, <value_in_kcal>],
"fats": <fats_in_g>,
"carbs": <carbs_in_g>,
"proteins": <proteins_in_g>,
"nbr_of_portions": <portions>
}
The name and the content of the calories array will be strings
, all other values will be floats
.
The function should return a json with the following format (Macros struct):
"cals": <calories>,
"carbs": <carbs>,
"proteins": <proteins>,
"fats": <fats>,
The number of portions should be taken into account. The values of the macros refer to one portion. All values should be floats (f64) and should be the addition of every macronutrient in the provided array (cals is the addition of every calories, fats is the addition of every fats, and so on...). Every value should be rounded to two decimal places (ex: 12.29) or one decimal place if it ends in 0 (ex: 18.90 -> 18.9).
Hint: You will need the serde
, serde_json
and serde_derive
crates.
Notions
Usage
Here is a program to test your function:
use macro_calculator::*;
fn main() {
let a = serde_json::json!(
{
"name": "light milk",
"calories": ["148kJ", "35kcal"],
"protein": 3.5,
"fats": 0.1,
"carbs": 5.0,
"nbr_of_portions": 0.7
});
let b = serde_json::json!({
"name": "oat cookies",
"calories": ["1996kJ", "477kcal"],
"protein": 8.2,
"fats": 21.0,
"carbs": 60.4,
"nbr_of_portions": 1.2,
});
let macros: Macros = serde_json::from_value(calculate_macros(vec![a, b])).unwrap();
println!("{:?}", macros);
}
And its output:
$ cargo run
Macros { cals: 596.9, carbs: 75.98, proteins: 12.29, fats: 25.27 }
$