static void ParseEquations(string input1 = "", string line2 = "")
{
bool valid = true;
char var1 = UNASSIGNED, var2 = UNASSIGNED; //blank space will be the default when it is unassigned
Matrix coefficients; //this will hold the coefficients for the variables
Matrix answers; //this will hold the answers for both equations
Matrix inverse; //this will hold the inverse of the coefficients matrix
Matrix varValues; //this will hold the values of the variables after solving for them
string input2 = line2; //second line user input
if (input1 != "")
{
WriteLine("Equation 1: " + input1 + "\n");
}
coefficients = new Matrix(2, 2); //initialize three matrices
coefficients = new Matrix(2, 2); //initialize three matrices
answers = new Matrix(2, 1); //initialize three matrices
try{ //parse first equation
Parsing.parseEquation(input1, coefficients, answers, ref var1, ref var2, true);
}
catch (ParseException e) {
WriteLine(e + "\n");
valid = false;
}
if (valid)
{
//Get second line and parse the variables
if (input2 == "")
{
Write("\nEnter the second equation \t--> ");
input2 = ReadLine();
}
else
{
WriteLine("Equation 2: " + input2 + "\n");
}
try{ //parse second equation
Parsing.parseEquation(input2, coefficients, answers, ref var1, ref var2, false);
}
catch (ParseException e) {
WriteLine(e + "\n");
valid = false;
}
if (valid)
{
WriteLine("\nThis is the coefficients matrix\n" + coefficients.ToString()); //output the values of the coefficients
try{
inverse = coefficients.Inverse(); //calculate the inverse of the coefficient matrix
WriteLine("This is the inverse of the coefficients matrix\n" + inverse.ToString());
WriteLine("This is the answers matrix\n" + answers.ToString());
varValues = inverse.Mult(answers); //find matrix X by doing coefficients.inverse * answers matrices
WriteLine("This is the solution of the multiplication of the inverse coefficients matrix and the answers matrix\n" + varValues.ToString());
WriteLine(var1 + " = " + varValues.GetCell(VAR1, 0));
WriteLine(var2 + " = " + varValues.GetCell(VAR2, 0));
}
catch (Exception e) {
WriteLine(e + "\nThe equations could not be calculated\n");
}
}
}
WriteLine("\nPress Enter to continue...");
ReadLine();
Clear();
}
/// <summary>
///This will take in one line, the two matrices to enter the values in, the variable characters and if it is the first line or not.
///it will parse it to get the one or two coefficients and the answer from the input
/// </summary>
/// <param name="input">This is the string that will be parsed to get</param>
/// <param name="coefficients">this matrix holds the values of the coefficients for the variables from both equations</param>
/// <param name="answers">this matrix holds the answers from both equations</param>
/// <param name="var1">this is the value of the first variable (it is ' ' if it has not been assigned)</param>
/// <param name="var2">this is the value of the second variable (it is ' ' if it has not been assigned)</param>
/// <param name="firstLine">this will determine if it is the first line to be parsed</param>
/// <returns>This only passes values by reference, there is no return</returns>
public static void parseEquation(string input, Matrix coefficients, Matrix answers, ref char var1, ref char var2, bool firstLine)
{
int index = 0;
double temp;
int line = (firstLine)? LINE1: LINE2; //this will determine which lines values are being parsed
char nextVar; //this will hold the other variable that has not been assigned on
int nextVarIndex;
temp = Parsing.parseCoefficient(input, ref index); //parse the string for the first coefficient
if (firstLine) //this means that var1 has not been assigned yet
{
#region Save first variable and coefficient
coefficients.SetCell(line, VAR1, temp); //assign the value for the first coefficient
var1 = Char.ToLower(input[index]); //get the variable at the index after the coefficient
#endregion
index++; //increment to check next character
#region Check second part of the equation for variable or answer
switch (input[index]) //is it the end of the equation or is there a second variable
{
#region go to answer
case '=': //no second coefficient, go straight to answer
coefficients.SetCell(line, VAR2, 0); //assign 0 to second variable
index++; //start the index after the equals sign for parsing
answers.SetCell(line, 0, Parsing.parseDouble(input, ref index)); //get the answer to the equation
break;
#endregion
#region save second coefficient and variable and answer
case '+': //there is a second variable
case '-':
#region save second coefficient and variable
temp = Parsing.parseCoefficient(input, ref index); //get second variable coefficient
if (input[index] == var1) //if the second variable is the same as the first throw an exception
{
throw new ParseException("Invalid characters detected, double use of the same variable!");
}
coefficients.SetCell(line, VAR2, temp);
var2 = Char.ToLower(input[index]); //store the second variable
index++; //increment to check next character
if (input[index] != '=')
{
throw new ParseException("Invalid characters detected at index " + index + ". Must be \"=\"");
}
else
{
index++; //increment to check next character
}
#endregion
#region save answer
answers.SetCell(line, 0, Parsing.parseDouble(input, ref index)); //get answer from the end of the input
#endregion
break;
default:
throw new ParseException("Invalid characters detected at index " + index);
#endregion
}
#endregion
}
else //this is the second line
{
#region check variable to assign coefficient
if (input[index] == var1) //assign to the coefficient corresponsing to the variable
{
coefficients.SetCell(line, VAR1, temp); //assign the value for the first coefficient
nextVar = Char.ToLower(var2);
nextVarIndex = VAR2;
}
else if (input[index] == var2)
{
coefficients.SetCell(line, VAR2, temp); //assign the value for the second coefficient
nextVar = Char.ToLower(var1);
nextVarIndex = VAR1;
}
else if (var2 == UNASSIGNED)
{
var2 = input[index]; //assign the previously empty var2
coefficients.SetCell(line, VAR2, temp);
nextVar = Char.ToLower(var1);
nextVarIndex = VAR1;
}
else
{
throw new ParseException("Invalid variable detected at line: " + line + ", index: " + index);
}
#endregion
index++; //increment to check next character
#region Check second part of the equation
switch (input[index]) //is it the end of the equation or is there a second variable
{
#region go to answer
case '=': //no second coefficient, go straight to answer
coefficients.SetCell(line, nextVarIndex, 0); //assign 0 to second variable
index++; //start the index after the equals sign for parsing
answers.SetCell(line, 0, Parsing.parseDouble(input, ref index)); //get the answer to the equation
break;
#endregion
#region save second coefficient and variable and answer
case '+': //there is a second variable
case '-':
#region save second coefficient and variable
coefficients.SetCell(line, nextVarIndex, Parsing.parseCoefficient(input, ref index)); //get second variable coefficient
if (input[index] != nextVar) //if the second variable is the same as the first throw an exception
{
throw new ParseException("Invalid characters detected, invalid second variable");
}
index++; //increment to check next character
if (input[index] != '=') //it needs to be an equal sign or is does not work
{
throw new ParseException("Invalid characters detected at index " + index + ". Must be \"=\"");
}
else
{
index++; //increment to check next character
}
#endregion
#region save answer
answers.SetCell(line, 0, Parsing.parseDouble(input, ref index));
#endregion
break;
default:
throw new ParseException("Invalid characters detected at index " + index);
#endregion
}
#endregion
}
}
