added a fibonacci program in BASIC

fibonacci_series/BASIC/fibonacci.bas

@@ -0,0 +1,27 @@
+' Fibonacci Sequence Generator in FreeBASIC
+
+Declare Function Fibonacci(ByVal n As Integer) As Integer
+
+' Main program
+Dim As Integer n, i
+
+Print "Enter the number of terms for Fibonacci sequence: ";
+Input n
+
+Print "Fibonacci of "; n; ": ";
+For i = 0 To n - 1
+    Print Fibonacci(i); " ";
+Next i
+
+Print  ' Print a newline at the end
+
+' Function to calculate Fibonacci number
+Function Fibonacci(ByVal n As Integer) As Integer
+    If n = 0 Then
+        Return 0
+    ElseIf n = 1 Then
+        Return 1
+    Else
+        Return Fibonacci(n - 1) + Fibonacci(n - 2)
+    End If
+End Function