Update and rename fibonacci.swift to fibonacciIterative.swift

Author: metacoder87

src/swift/fibonacci.swift

@@ -0,0 +1,21 @@
+// Function to calculate Fibonacci numbers iteratively
+func fibonacciIterative(_ number: Int) -> Int {
+    if number <= 1 {
+        return number
+    } else {
+        var currentNumber: Int = 1
+        var nextNumber: Int = 0
+        
+        // Iterate from 0 to 'number - 1'
+        for _ in 0..<number {
+            let tempNumber = nextNumber
+            nextNumber = nextNumber + currentNumber
+            currentNumber = tempNumber
+        }
+        
+        return currentNumber
+    }
+}
+
+let index: Int = 15
+print("Fibonacci (iterative):", fibonacciIterative(index))