public static bool checkInputString(string formula)
{
int counter1 = 0,
counter2 = 2;
if (SignChecker.isOperation(formula[0]) && formula[0] != '-')
{
return(false);
}
if (SignChecker.isOperation(formula[formula.Length - 1]))
{
return(false);
}
counter1 = formula.ToCharArray().Where(x => x == '(').Count();
counter2 = formula.ToCharArray().Where(x => x == ')').Count();
if (counter1 != counter2)
{
return(false);
}
for (int i = 1; i < formula.Length; i++)
{
if (SignChecker.isOperation(formula[i]) && SignChecker.isOperation(formula[i - 1]))
{
return(false);
}
}
return(true);
}
//Checks function
public static bool checkInputString(string formula)
{
int counter1 = 0,
counter2 = 2;
//Returns false if first symbol in function is operation (besides minus)
if (SignChecker.isOperation(formula[0]) && formula[0] != '-')
{
return(false);
}
//Returs false if last symbol in string is operation
if (SignChecker.isOperation(formula[formula.Length - 1]))
{
return(false);
}
//Counts ammount of opening and closing brackets
counter1 = formula.ToCharArray().Where(x => x == '(').Count();
counter2 = formula.ToCharArray().Where(x => x == ')').Count();
//If ammount of brackets doesn't equal, then returns false
if (counter1 != counter2)
{
return(false);
}
//Checks if there is no two operations side by side
for (int i = 1; i < formula.Length; i++)
{
if (SignChecker.isOperation(formula[i]) && SignChecker.isOperation(formula[i - 1]))
{
return(false);
}
}
return(true);
}
public static string toRPN(string infixString)
{
if (!CheckInput.checkInputString(infixString))
{
return("");
}
Stack <char> operationStack = new Stack <char>(); //Stack for all operations
char lastOperation;
string resultString = ""; //String with result
infixString = infixString.Replace(" ", "");
for (int i = 0; i < infixString.Length; i++)
{
//If it is number, than add to resultString
if (SignChecker.isVariable(infixString[i]))
{
resultString += infixString[i];
}
else if (SignChecker.isOperation(infixString[i]))
{
if (infixString[i] == '-' && (((i == 0) || (infixString[i - 1] == '(')) && (SignChecker.isVariable(infixString[i + 1]))))
{
resultString += 0;
}
if (operationStack.Count != 0)
{
lastOperation = operationStack.Peek();
if (SignChecker.getOperationPriority(lastOperation) < SignChecker.getOperationPriority(infixString[i]))
{
operationStack.Push(infixString[i]);
resultString += " ";
}
else
{
resultString += operationStack.Pop();
operationStack.Push(infixString[i]);
resultString += " ";
}
}
else
{
resultString += " ";
operationStack.Push(infixString[i]);
}
}
//If current symbol is (, then add it to stack
else if (infixString[i] == '(')
{
operationStack.Push(infixString[i]);
}
//If current symbol is ), then return all symbols from stack, until (
else if (infixString[i] == ')')
{
while (operationStack.Peek() != '(')
{
resultString += operationStack.Pop();
}
operationStack.Pop();
}
}
//In the end, return all the values from stack
while (operationStack.Count != 0)
{
resultString += operationStack.Pop() + " ";
}
return(resultString);
}
public static string toRPN(string infixString)
{
infixString = infixString.Replace(" ", ""); //Replacing all spaces
if (!CheckInput.checkInputString(infixString)) //If we have wrong input string
{
throw new ArgumentException(); //Than throw exception
}
Stack <char> operationStack = new Stack <char>(); //Stack for all operations
char lastOperation; //Keeping last operation
string resultString = ""; //String with result
for (int i = 0; i < infixString.Length; i++)
{
//If it is number, than add to resultString
if (SignChecker.isVariable(infixString[i]))
{
resultString += infixString[i];
}
//If it is operation
else if (SignChecker.isOperation(infixString[i]))
{
//If it is unary minus< then add 0 to result string
if (infixString[i] == '-' && (((i == 0) || (infixString[i - 1] == '(')) && (SignChecker.isVariable(infixString[i + 1]))))
{
resultString += 0;
}
//If we have operations in stack
if (operationStack.Count != 0)
{
//Taking last operation of stack
lastOperation = operationStack.Peek();
//If priority of operation from stack is higher, then pirority of current operation
if (SignChecker.getOperationPriority(lastOperation) < SignChecker.getOperationPriority(infixString[i]))
{
//Add current operation to stack
operationStack.Push(infixString[i]);
resultString += " ";
}
else
{
//Add operation from stack to result string
resultString += operationStack.Pop();
//Add current operation to stack
operationStack.Push(infixString[i]);
resultString += " ";
}
}
else
{
//Add current operation to stack
resultString += " ";
operationStack.Push(infixString[i]);
}
}
//If current symbol is (, then add it to stack
else if (infixString[i] == '(')
{
operationStack.Push(infixString[i]);
}
//If current symbol is ), then return all symbols from stack, until (
else if (infixString[i] == ')')
{
while (operationStack.Peek() != '(')
{
resultString += operationStack.Pop();
}
operationStack.Pop();
}
}
//In the end, return all the values from stack
while (operationStack.Count != 0)
{
resultString += operationStack.Pop() + " ";
}
return(resultString);
}