public IList <IInstruction> Parse(string input)
{
List <IInstruction> instructions = new List <IInstruction>();
//e.g. LMLMLMLMM
foreach (char c in input.ToUpper())
{
IInstruction newInstruction = new NullInstruction();;
switch (c)
{
case 'L':
newInstruction = new LeftInstruction();
break;
case 'M':
newInstruction = new MoveInstruction();
break;
case 'R':
newInstruction = new RightInstruction();
break;
default:
break;
}
instructions.Add(newInstruction);
}
return(instructions);
}
private static int[] Compute(int[] input)
{
int i = 0;
int opcode = -1;
while (i < input.Length && opcode != 99)
{
Instruction instruction = new NullInstruction(input, i);
opcode = input[i] % 100;
var fullOpCode = input[i];
switch (opcode)
{
case 99: break;
case 1:
instruction = new Add(input, i);
break;
case 2:
instruction = new Multiply(input, i);
break;
case 3:
instruction = new Input(input, i);
break;
case 4:
instruction = new Output(input, i);
break;
case 5:
instruction = new JumpIfTrue(input, i);
break;
case 6:
instruction = new JumpIfFalse(input, i);
break;
case 7:
instruction = new LessThan(input, i);
break;
case 8:
instruction = new Equal(input, i);
break;
default: throw new ArgumentException();
}
(var newInput, var instructionPointer) = instruction.Compute();
i = instructionPointer;
input = newInput;
}
return(input);
}
