From b65a2ae726a67f498a934d0c0124297a23e42461 Mon Sep 17 00:00:00 2001
From: Syndamia <kamen@syndamia.com>
Date: Mon, 17 Oct 2022 19:09:31 +0300
Subject: [SDP/P02] Solved exercises from second practicum

---
 .../02-Practicum-12.10.2022.cpp                    | 141 +++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 Year 2/Structures and data algorithms/02-Practicum-12.10.2022.cpp

diff --git a/Year 2/Structures and data algorithms/02-Practicum-12.10.2022.cpp b/Year 2/Structures and data algorithms/02-Practicum-12.10.2022.cpp
new file mode 100644
index 0000000..5962c93
--- /dev/null
+++ b/Year 2/Structures and data algorithms/02-Practicum-12.10.2022.cpp	
@@ -0,0 +1,141 @@
+#include <iostream>
+#include <cstring>
+
+template <class T>
+class StackElem {
+	T data;
+	StackElem* next;
+
+public:
+	StackElem(T data) : StackElem(data, nullptr) {}
+	StackElem(T data, StackElem* se) : data(data), next(se) {}
+	~StackElem() = default;
+	StackElem(StackElem& other) = delete;
+	StackElem& operator=(StackElem& other) = delete;
+
+	const T& get_data() { return this->data; }
+	StackElem* get_next() { return this->next; }
+	void set_next(StackElem* next) { this->next = next; }
+};
+
+template <class T>
+class Stack {
+	StackElem<T>* topPtr;
+	StackElem<T>* startPtr;
+
+public:
+	Stack() : topPtr(), startPtr() {}
+	Stack(Stack& other) = delete;
+	~Stack() {
+		StackElem<T>* temp;
+		while (startPtr != nullptr) {
+			temp = startPtr->get_next();
+			delete startPtr;
+			startPtr = temp;
+		}
+	}
+	Stack& operator=(Stack& other) = delete;
+
+	void push(T value) {
+		if (topPtr == nullptr)
+			startPtr = topPtr = new StackElem<T>(value);
+		else {
+			topPtr->set_next(new StackElem<T>(value));
+			topPtr = topPtr->get_next();
+		}
+	}
+
+	T pop() {
+		if (topPtr == nullptr) return T();
+
+		T temp = topPtr->get_data();
+		if (startPtr == topPtr) {
+			delete topPtr;
+			startPtr = topPtr = nullptr;
+			return temp;
+		}
+
+		StackElem<T>* prevDel = startPtr;
+		while (prevDel->get_next() != topPtr)
+			prevDel = prevDel->get_next();
+
+		delete topPtr;
+		topPtr = prevDel;
+		prevDel->set_next(nullptr);
+		return temp;
+	}
+
+	T top() {
+		if (topPtr == nullptr) return T();
+
+		return topPtr->get_data();
+	}
+};
+
+// Exercise 1
+
+void ex1() {
+	const char* str = "thi*s i*s exampl*e";
+	unsigned strLen = strlen(str);
+
+	Stack<char> parsedStr;
+	for (unsigned i = 0; i < strLen; i++) {
+		if (str[i] == '*') parsedStr.pop();
+		else parsedStr.push(str[i]);
+	}
+
+	while (parsedStr.top() != char())
+		std::cout << parsedStr.pop();
+	std::cout << std::endl;
+}
+
+// Exercise 2
+
+void ex2() {
+	const char* str = "()()(())";
+	unsigned strLen = strlen(str);
+
+	Stack<char> brackets;
+	for (unsigned i = 0; i < strLen; i++) {
+		if (str[i] == '(') brackets.push('(');
+		else if (str[i] == ')') brackets.pop();
+	}
+
+	if (brackets.top() != '(')
+		std::cout << "Balanced" << std::endl;
+	else
+		std::cout << "Unbalanced" << std::endl;
+}
+
+// Exercise 3
+
+void ex3() {
+	const char* str = "1 2 - 3 + 10 *";
+
+	Stack<int> calc;
+	while (*str != '\0') {
+		if (*str >= '0' && *str <= '9') {
+			calc.push(atoi(str));
+			while (*str >= '0' && *str <= '9')
+				str++;
+		}
+		else if (*str == '+')
+			calc.push(calc.pop() + calc.pop());
+		else if (*str == '-')
+			calc.push(calc.pop() - calc.pop());
+		else if (*str == '*')
+			calc.push(calc.pop() * calc.pop());
+		else if (*str == '/')
+			calc.push(calc.pop() / calc.pop());
+		else if (*str == '%')
+			calc.push(calc.pop() % calc.pop());
+
+		str++;
+	}
+
+	std::cout << calc.top() << std::endl;
+}
+
+int main() {
+	ex3();
+}
-- 
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