Added Ex 9,10 for If

10_if2.zig

@@ -0,0 +1,20 @@
+//
+// If statements are also valid expressions:
+//
+//   foo = if (a) 2 else 3;
+//
+// Note: you'll need to declare a variable type when assigning a value
+// from a statement like this because the compiler isn't smart enough
+// to infer the type for you.
+//
+const std = @import("std");
+
+pub fn main() void {
+    var discount = true;
+
+    // If discount is true, the price should be $17, otherwise $20:
+    var price = if ???;
+
+    std.debug.print("With the discount, the price is ${}.\n", .{price});
+}
+