Initial update

.devcontainer/.Dockerfile

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+FROM rust:latest

.devcontainer/devcontainer.json

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+{
+    "name": "Sample Rust",
+    "build": {
+        "dockerfile": "Dockerfile"
+    },
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "rust-lang.rust-analyzer", // Updated to use rust-analyzer
+                "ms-azuretools.vscode-docker" // Added Docker extension
+            ]
+        }
+    },
+    "postCreateCommand": "rustup update && rustup component add clippy && rustup component add rustfmt"
+}

.github/workflows/ci.yaml

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+name: CI/CD
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v3
+
+    - name: Install Rust
+      uses: actions-rs/toolchain@v1
+      with:
+        toolchain: stable
+        override: true
+
+    - name: Check
+      run: make check
+
+    - name: Format
+      run: make format
+
+    - name: Test
+      run: make test
+
+    - name: Release
+      run: cargo build --release
+
+    - name: Upload Binary Artifact
+      uses: actions/upload-artifact@v4 #v3 is scheduled for deprecation Nov 30 2024 check marketplace
+      with:
+        name: Rust Artificat Binary
+        path: target/release/loan_payment

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "loan_payment"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+clap = { version = "4.1", features = ["derive"] }

Makefile

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+format:
+	rustfmt src/main.rs
+	rustfmt src/lib.rs
+check:
+	cargo check
+test:
+	cargo test
+lint:
+	cargo clippy

src/lib.rs

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+// src/lib.rs
+
+// Function to calculate the monthly interest rate
+pub fn calculate_monthly_rate(annual_rate: f64) -> f64 {
+    annual_rate / 12.0
+}
+
+// Function to calculate the discount factor for the loan
+pub fn calculate_discount_factor(monthly_rate: f64, periods: i32) -> f64 {
+    if monthly_rate == 0.0 {
+        1.0  // If there's no interest rate, the discount factor doesn't apply
+    } else {
+        1.0 - (1.0 + monthly_rate).powi(-periods)
+    }
+}
+
+// Function to calculate the monthly loan payment
+pub fn get_monthly_payment(principal: f64, rate: f64, periods: i32) -> f64 {
+    let monthly_rate = calculate_monthly_rate(rate);
+
+    // Handle the case where interest rate is zero
+    if rate == 0.0 {
+        principal / periods as f64
+    } else {
+        let discount_factor = calculate_discount_factor(monthly_rate, periods);
+        (principal * monthly_rate) / discount_factor
+    }
+}
+
+// Unit tests for the above functions
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_calculate_monthly_rate() {
+        // Test with a typical annual rate
+        assert_eq!(calculate_monthly_rate(0.12), 0.01);
+
+        // Test with a 0% annual rate
+        assert_eq!(calculate_monthly_rate(0.0), 0.0);
+
+        // Test with a negative annual rate
+        assert_eq!(calculate_monthly_rate(-0.12), -0.01);
+    }
+
+    #[test]
+    fn test_calculate_discount_factor() {
+        // Test with a typical input
+        let discount_factor = calculate_discount_factor(0.01, 12);
+
+        // Test with zero monthly rate (discount factor should be 1.0)
+        assert_eq!(calculate_discount_factor(0.0, 12), 1.0);
+    }
+
+    #[test]
+    fn test_get_monthly_payment() {
+        // Test with typical inputs
+        let payment = get_monthly_payment(100000.0, 0.05, 360);
+        assert!((payment - 536.82).abs() < 0.01);  // Margin of error
+
+        // Test with zero interest rate (adjusted logic)
+        assert_eq!(get_monthly_payment(100000.0, 0.0, 360), 277.77777777777777);  // Principal / periods
+    }
+}