public Fraction DivideFractions()
{
fraction = userInterface.getFraction();
fraction2 = userInterface.getFraction();
result.Allocate(fraction.Divide(fraction2));
return(result);
}
/// <summary>
/// Runs through an array of MathNodes executing the supplied operator only. Not perfect... i think multiplication and division are same priority
/// </summary>
/// <param name="input"></param>
/// <param name="op"></param>
/// <returns></returns>
internal static MathNode[] ProcessOperator(MathNode[] input, string op)
{
int elements = input.Length;
var ret = new List <MathNode>();
for (var i = 0; i < input.Length; i++)
{
if (input[i].NodeType == Enums.NodeType.Operation && input[i].Operator == op)
{
Fraction?temp = null;
if (OperatorHasLeftAndRightMovesAvailable(i, input.Length))
{
//Make sure an operator is surrounded by numbers only
if (input[i - 1].NodeType != Enums.NodeType.Fraction || input[i + 1].NodeType != Enums.NodeType.Fraction)
{
throw new InvalidOperationException($"Tried to process an operator not surrounded by 2 numbers. i {i}, node types: {input[i - 1].NodeType}, {input[i].NodeType}, {input[i + 1].NodeType}");
}
Fraction last = (Fraction)input[i - 1].Value;
Fraction next = (Fraction)input[i + 1].Value;
if (last == null || next == null)
{
throw new InvalidOperationException($"Tried to process a null number node. i {i}, last: {last}, next: {next}");
}
switch (op)
{
case OperatorConsts.DIVIDE:
//Need to test for divide by 0,
if (next == 0)
{
throw new InvalidOperationException($"About to divide by 0 {last}/{next}");
}
else
{
temp = last.Divide(next);
break;
}
case OperatorConsts.MULTIPLY:
temp = last.Multiply(next);
break;
case OperatorConsts.PLUS:
temp = last.Add(next);
break;
case OperatorConsts.MINUS:
temp = last.Subtract(next);
break;
}
//TODO: there is a better way to do this, can't think of it at the moment. We already added the previous node to the ret list. Yank it out.
//Add this number. And then, skip i ahead 1 because that way we skip over the processing of the next numeric node which will be a no-op, and
//add an entry in the ret list
ret.RemoveAt(ret.FindLastIndex(x => x.NodeType == Enums.NodeType.Fraction && x.Value == last));
ret.Add(new MathNode((Fraction)temp));
i++;
}
else
{
//Would use some normal logging...
Debug.WriteLine($"On index {i}, input is {input.Length} long, node type {input[i].NodeType}, operator? {input[i].Operator}, number? {input[i].Value}");
throw new InvalidOperationException($"Operator with no available next or previous fraction node. On index {i}, input is {input.Length}");
}
}
else
{
ret.Add(input[i]);
}
}
return(ret.ToArray());
}