sem 15

1 files changed, 77 insertions, 0 deletions

diff --git a/Sem. 15/ExpessionCalculator/ExpressionCalculator.cpp b/Sem. 15/ExpessionCalculator/ExpressionCalculator.cpp
new file mode 100644
index 0000000..86c68c8
--- /dev/null
+++ b/Sem. 15/ExpessionCalculator/ExpressionCalculator.cpp
@@ -0,0 +1,77 @@
+#include "ExpressionCalculator.h"
+
+void ExpressionCalculator::copyFrom(const ExpressionCalculator& other)
+{
+	expr = other.expr->clone();
+}
+
+void ExpressionCalculator::free()
+{
+	delete expr;
+}
+
+bool isOperator(char ch)
+{
+	return ch == AND || ch == OR || ch == IFF || ch == IMPL || ch == XOR || ch == NEG;
+}
+
+ExpressionCalculator::BooleanExpr* parse(const MyString& str)
+{
+
+	if (str.getSize() == 1)
+	{
+		return new ExpressionCalculator::Variable(str[0]);
+	}
+
+	MyString strWithoutBrackets = str.subString(1, str.getSize() - 2); //We remove the brackets.
+
+	
+	int countBrackets = 0;
+	for (size_t i = 0; i < strWithoutBrackets.getSize(); i++) //we start searching for the operation.
+	{														 // then we split to two expressions
+		if (strWithoutBrackets[i] == '(')
+			countBrackets++;
+		else if (strWithoutBrackets[i] == ')')
+			countBrackets--;
+		else if (isOperator(strWithoutBrackets[i]) && countBrackets == 0)
+		{
+			if (strWithoutBrackets[i] == NEG)
+				return new ExpressionCalculator::UnaryOperation('!', parse(strWithoutBrackets.subString(i + 1, strWithoutBrackets.getSize() - 1)));
+			else
+				return new ExpressionCalculator::BinaryOperation(parse(strWithoutBrackets.subString(0, i - 1)), strWithoutBrackets[i], parse(strWithoutBrackets.subString(i+1, strWithoutBrackets.getSize() - 1)));
+		}
+
+	}
+}
+
+ExpressionCalculator::ExpressionCalculator(const MyString& str)
+{
+	expr = parse(str);
+
+}
+ExpressionCalculator::ExpressionCalculator(const ExpressionCalculator& other)
+{
+	copyFrom(other);
+}
+ExpressionCalculator& ExpressionCalculator::operator=(const ExpressionCalculator& other)
+{
+	if (this != &other)
+	{
+		free();
+		copyFrom(other);
+	}
+	return *this;
+}
+ExpressionCalculator::~ExpressionCalculator()
+{
+	free();
+}
+
+bool ExpressionCalculator::isTautology() const
+{
+	return checkAll(expr, true);
+}
+bool ExpressionCalculator::isContradiction() const
+{
+	return checkAll(expr, false);
+}
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