Added solutions from oop seminar 2

1 files changed, 167 insertions, 0 deletions

diff --git a/Year 1/Object-oriented Programming/Solutions Sem. 02/exercise03.cpp b/Year 1/Object-oriented Programming/Solutions Sem. 02/exercise03.cpp
new file mode 100644
index 0000000..07e7c9e
--- /dev/null
+++ b/Year 1/Object-oriented Programming/Solutions Sem. 02/exercise03.cpp
@@ -0,0 +1,167 @@
+#include <iostream> // cin, cout
+#include <fstream>  // ifstream, ofstream
+
+const int LINE_BUFFER_SIZE = 1024;
+const int MAX_STUDENT_PROP_SIZE = 2048;
+
+bool strNotEqual(const char* a, const char* b) {
+	for (int i = 0; a[i] != '\0' || b[i] != '\0'; i++)
+		if (a[i] != b[i]) return true;
+	return false;
+}
+
+/* Student */
+
+struct Student {
+	char FirstName[MAX_STUDENT_PROP_SIZE];
+	char LastName[MAX_STUDENT_PROP_SIZE];
+	char Email[MAX_STUDENT_PROP_SIZE];
+	char FN[MAX_STUDENT_PROP_SIZE];
+};
+
+void printStudent(Student st) {
+	std::cout << "Name = " << st.FirstName << " " << st.LastName << ", Email: " << st.Email << ", FN: " << st.FN << std::endl; 
+}
+
+Student parseStudent(const char* str) {
+	Student toRet = {};
+	char* prop = toRet.FirstName;
+
+	for (int i = 0, j = 0; str[i] != '\0'; i++) {
+		if (str[i] == ',') {
+			if (prop == toRet.FirstName) prop = toRet.LastName;
+			else if (prop == toRet.LastName) prop = toRet.Email;
+			else if (prop == toRet.Email) prop = toRet.FN;
+			j = 0;
+		}
+		else prop[j++] = str[i];
+	}
+	return toRet;
+}
+
+/* StudentsList */
+
+struct StudentsList {
+	Student* students;
+	int count;
+	int length;
+};
+
+bool resizeStudentsList(StudentsList& sl, int newSize) {
+	if (newSize < sl.count) return false; // We cant fit all of the old students in the new students array
+
+	Student* temp = new Student[newSize];
+	for (int i = 0; i < sl.count; i++)
+		temp[i] = sl.students[i];
+
+	delete[] sl.students;
+	sl.students = temp;
+
+	return true;
+}
+
+void addStudents(StudentsList& sl, Student st) {
+	if (sl.count == sl.length) {
+		sl.length = (!sl.length) ? 2 : sl.length << 1;
+		resizeStudentsList(sl, sl.length);
+	}
+
+	sl.students[sl.count++] = st;
+}
+
+int findStudentIndByFN(const StudentsList& sl, const char* FN) {
+	for (int i = 0; i < sl.count; i++)
+		if (strNotEqual(sl.students[i].FN, FN)) return i;
+
+	std::cout << "Error: No student with FN of " << FN << "!" << std::endl;
+	return -1;
+}
+
+StudentsList getStudentsListFromFile(const char* fileName) {
+	std::ifstream inFile(fileName);
+	if (!inFile.is_open()) {
+		std::cout << "Error: Could not open file!" << std::endl;
+		return {};
+	}
+
+	StudentsList sl = {};
+
+	char buffer[LINE_BUFFER_SIZE];
+	while (!inFile.eof()) {
+		inFile.getline(buffer, LINE_BUFFER_SIZE);
+		if (buffer[0] != '\0')
+			addStudents(sl, parseStudent(buffer));
+	}
+	return sl;
+}
+
+/* Commands */
+
+bool isCommand(const char* inputBuffer, const char* command) { // The buffer could get dirty with leftover data, so we check only if the beginning matches
+	for (int i = 0; command[i] != '\0'; i++)
+		if (inputBuffer[i] != command[i]) return false;
+
+	return true;
+}
+
+void printStudentByFN(const StudentsList& sl, const char* FN) {
+	int stInd = findStudentIndByFN(sl, FN);
+	if (stInd >= 0) printStudent(sl.students[stInd]);
+}
+
+void replaceStudentEmail(const StudentsList& sl, const char* FN, const char* newEmail) {
+	int stdInd = findStudentIndByFN(sl, FN);
+	if (stdInd < 0) return;
+
+	Student& st = sl.students[stdInd];
+	for (int i = 0; st.Email[i] != '\0' || newEmail[i] != '\0'; i++)
+		st.Email[i] = (newEmail[i] == '\0') ? '\0' : newEmail[i];
+}
+
+void saveToFile(const StudentsList& sl, const char* newFileName) {
+	std::ofstream newFile(newFileName);
+	if (!newFile.is_open()) {
+		std::cout << "Error: File could not be opened!" << std::endl;
+		return;
+	}
+
+	for (int i = 0; i < sl.count; i++) {
+		Student st = sl.students[i];
+		newFile << st.FirstName << "," << st.LastName << "," << st.Email << "," << st.FN << std::endl;
+	}
+
+	newFile.close();
+}
+
+/* Main */
+
+int main() {
+	char inputBuffer[LINE_BUFFER_SIZE];
+	std::cout << "Open file:" << std::endl << ">";
+	std::cin >> inputBuffer;
+
+	StudentsList readSL = getStudentsListFromFile(inputBuffer);
+	if (readSL.students == nullptr)
+		return -1;
+
+	do {
+		std::cout << ">";
+		std::cin >> inputBuffer;
+
+		if (isCommand(inputBuffer, "print")) {
+			std::cin >> inputBuffer;
+			printStudentByFN(readSL, inputBuffer);
+		}
+		else if (isCommand(inputBuffer, "edit")) {
+			char tempFNBuffer[LINE_BUFFER_SIZE];
+			std::cin >> tempFNBuffer >> inputBuffer;
+			replaceStudentEmail(readSL, tempFNBuffer, inputBuffer);
+		}
+		else if (isCommand(inputBuffer, "save")) {
+			std::cin >> inputBuffer;
+			saveToFile(readSL, inputBuffer);
+		}
+	} while (!isCommand(inputBuffer, "end"));
+
+	delete[] readSL.students;
+}