mutable vars

challenges/challenges.json

@@ -23,6 +23,18 @@
     "created_at": "2024-06-07T00:00:00Z",
     "updated_at": "2024-06-07T00:00:00Z"
   },
+  {
+    "id": 23,
+    "title": "Mutable Variables",
+    "slug": "mutable-variables",
+    "short_description": "Declare and manipulate mutable variables in Rust.",
+    "language": "RUST",
+    "difficulty": "EASY",
+    "track": "RUST_BASICS",
+    "tags": [],
+    "created_at": "2024-06-08T00:00:00Z",
+    "updated_at": "2024-06-08T00:00:00Z"
+  },
   {
     "id": 2,
     "title": "Character counting string",

challenges/mutable-variables/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "mutable-variables"
+version = "0.1.0"
+edition = "2021"
+
+[dev-dependencies]
+syntest = { path = "../../crates/syntest" }

challenges/mutable-variables/description.md

@@ -0,0 +1,41 @@
+## Mutable Variables Challenge
+
+Declaring and manipulating variables in programming is a fundamental concept that allows you to store and modify data. Variables in Rust are immutable by default, but you can make them mutable using the `mut` keyword.
+
+In this challenge, you will declare and use mutable variables in Rust. You will be given a function where you need to declare variables, modify their values, and perform specific operations.
+
+## Your task
+
+In this challenge, you need to declare two mutable variables inside the function using the `let mut` keyword:
+
+- `x` with an initial value of `5`
+- `y` with an initial value of `10`
+
+Then, perform the following operations:
+
+1. Increment `x` by `10`
+2. Multiply `y` by `2`
+
+Finally, calculate the sum of `x` and `y` and return the result.
+
+## Requirements
+
+- Declare two mutable variables, `x` and `y`, and assign them initial values.
+- Increment `x` by `10`.
+- Multiply `y` by `2`.
+- Calculate the sum of `x` and `y`.
+- Return the calculated sum.
+
+## Example
+
+```rust
+let result = manipulate_variables();
+assert_eq!(result, 35);
+```
+
+## Hints
+
+- Use the let mut keyword to declare mutable variables.
+- Use the += operator to increment a variable.
+- Use the \*= operator to multiply a variable.
+- Calculate the sum of x and y using the + operator.

challenges/mutable-variables/src/lib.rs

@@ -0,0 +1,9 @@
+pub fn manipulate_variables() -> i32 {
+    let mut x = 5;
+    let mut y = 10;
+
+    x += 10;
+    y += 2;
+
+    x + y
+}

challenges/mutable-variables/src/starter.rs

@@ -0,0 +1,8 @@
+pub fn manipulate_variables() -> i32 {
+    // TODO: Implement the function here
+    // Declare x and y as mutable variables
+    // Increment x by 10
+    // Multiply y by 2
+    // Calculate the sum of x and y
+    // Return the calculated sum
+}

challenges/mutable-variables/tests/tests.rs

@@ -0,0 +1,48 @@
+#[cfg(test)]
+mod tests {
+    use mutable_variables::*;
+    use syntest::{LocalVariable, Mutation, Syntest, Value};
+
+    #[test]
+    fn test_compiles() {
+        manipulate_variables();
+    }
+
+    #[test]
+    fn test_variables() {
+        let syntest = Syntest::from("./src/lib.rs");
+
+        // Expect the 2 variables to exist
+        syntest
+            .variables("manipulate_variables")
+            .iter()
+            .for_each(|var| match var {
+                LocalVariable::Int { .. } => match var.name() {
+                    "x" => {
+                        assert_eq!(var.value(), Value::Int(15));
+                        assert_eq!(var.is_used(), true);
+                        assert_eq!(var.is_mutable(), true);
+                        assert_eq!(
+                            var.mutations(),
+                            &vec![Mutation::new(Value::Int(5), Value::Int(15))]
+                        );
+                    }
+                    "y" => {
+                        assert_eq!(var.value(), Value::Int(12));
+                        assert_eq!(var.is_used(), true);
+                        assert_eq!(var.is_mutable(), true);
+                        assert_eq!(
+                            var.mutations(),
+                            &vec![Mutation::new(Value::Int(10), Value::Int(12))]
+                        );
+                    }
+                    _ => {
+                        panic!("Expected an integer variable")
+                    }
+                },
+                _ => {
+                    panic!("Expected an integer variable")
+                }
+            })
+    }
+}