feat: added absolute value and square root

src/gcalc.gleam

@@ -1,5 +1,5 @@
 import gleam/io
 
 pub fn main() {
-  io.println("Hello from calc!")
+  io.println("Hello from gcalc!")
 }

src/gcalc/alg.gleam

@@ -1,5 +1,7 @@
 //// A set of algebraic operations for the for Gleam programs
 
+import gleam/float
+
 /// Return the exponentiation of the two arguments
 pub fn pow(base: Int, power: Int, accumulator: Int) -> Int {
   case power {
@@ -15,3 +17,36 @@ pub fn factorial(n: Int) -> Int {
     _ -> n * factorial(n - 1)
   }
 }
+
+/// Return the square root of the argument
+pub fn sqrt(n: Float) -> Float {
+  case n {
+    0.0 -> 0.0
+    _ -> {
+      let x0 = n /. 2.0
+      let x1 = { x0 +. n /. x0 } /. 2.0
+      sqrt_iter(x0, x1, n)
+      |> float.floor()
+    }
+  }
+}
+
+/// Helper function for the square root function
+fn sqrt_iter(x0: Float, x1: Float, n: Float) -> Float {
+  case abs(x1 -. x0) <. 0.0001 {
+    True -> x1
+    False -> {
+      let x0 = x1
+      let x1 = { x0 +. n /. x0 } /. 2.0
+      sqrt_iter(x0, x1, n)
+    }
+  }
+}
+
+/// Return the absolute value of the argument
+pub fn abs(n: Float) -> Float {
+  case n <. 0.0 {
+    True -> 0.0 -. n
+    False -> n
+  }
+}

test/gcalc_test.gleam

@@ -53,3 +53,39 @@ pub fn factorial_5_test() {
   alg.factorial(5)
   |> should.equal(120)
 }
+
+/// Test that sqrt(4) = 2
+pub fn sqrt_4_test() {
+  alg.sqrt(4.0)
+  |> should.equal(2.0)
+}
+
+/// Test that sqrt(9) = 3
+pub fn sqrt_9_test() {
+  alg.sqrt(9.0)
+  |> should.equal(3.0)
+}
+
+/// Test that sqrt(16) = 4
+pub fn sqrt_16_test() {
+  alg.sqrt(16.0)
+  |> should.equal(4.0)
+}
+
+/// Test that |3| = 3
+pub fn abs_3_test() {
+  alg.abs(3.0)
+  |> should.equal(3.0)
+}
+
+/// Test that |-3| = 3
+pub fn abs_neg3_test() {
+  alg.abs(-3.0)
+  |> should.equal(3.0)
+}
+
+/// Test that |0| = 0
+pub fn abs_0_test() {
+  alg.abs(0.0)
+  |> should.equal(0.0)
+}