calculate change

src/main/java/tech/iBeans/POSware/Lite/payment.java

@@ -4,4 +4,46 @@ package tech.iBeans.POSware.Lite;
 import java.util.*;
 import java.math.*;
 
-public class payment{};
+public class payment{
+	public static Float total = null;
+	public static Float change = null;
+	public static Float in = null;
+
+	public static void init() {
+		/* Set up the payment.  */
+		change = (float) 0;
+		in = (float) 0;
+	};
+
+	public static Float calculate() {
+		/* Calculate the change. 
+		 * 
+		 * Returns: (float) the calculated change
+		 */
+
+
+		if (total > in) {return (null);}; // Do not calculate a smaller change. 
+		change = in - total;
+		return(change);	
+	};
+
+	public static Float calculate(float TOTAL, float IN) {
+		/* Calculate the change from a provided total and input. 
+		 * 
+		 * Returns: (float) the calculated change
+		 */
+
+		total = TOTAL; 
+		in = IN;
+
+		return(calculate());
+	};
+
+	public static void log() {
+		/* Log the payment.
+		*/
+
+		// TODO add payment processing here. 
+	};
+
+};