minor fixes

1 files changed, 253 insertions, 0 deletions

diff --git a/Sem. 02/task2/studentsDatabase.cpp b/Sem. 02/task2/studentsDatabase.cpp
new file mode 100644
index 0000000..7f9a5f5
--- /dev/null
+++ b/Sem. 02/task2/studentsDatabase.cpp
@@ -0,0 +1,253 @@
+#include <iostream>
+#include <fstream>
+
+using namespace std;
+
+const int FIELD_MAX_SIZE = 50;
+const int BUFFER_LINE_SIZE = 1024;
+
+struct OOPstudent
+{
+	char firstName[FIELD_MAX_SIZE];
+	char lastName[FIELD_MAX_SIZE];
+	char email[FIELD_MAX_SIZE];
+	int fn = 0;
+
+};
+
+int countLines(const char* fileName)
+{
+	ifstream f(fileName);
+	if (!f.is_open())
+		return -1;
+	int linesCount = 0;
+
+	while (!f.eof())
+	{
+		char buff[1024];
+		f.getline(buff, 1024);
+		linesCount++;
+	}
+	f.close();
+
+	return linesCount;
+
+}
+// abc,bcd,ab@Abv.bg,fn
+void readStudent(const char* input, OOPstudent& student)
+{
+	int ind = 0;
+
+	// first name
+	while (input[ind] != ',')
+	{
+		student.firstName[ind] = input[ind];
+		ind++;
+	}
+	student.firstName[ind] = '\0';
+	ind++;
+
+	//last name
+	int lastNameInd = 0;
+	while (input[ind] != ',')
+		student.lastName[lastNameInd++] = input[ind++];
+	student.lastName[lastNameInd] = '\0';
+	ind++;
+
+	//email
+	int emailInd = 0;
+
+	while (input[ind] != ',')
+		student.email[emailInd++] = input[ind++];
+	student.email[emailInd] = '\0';
+	ind++;
+
+	//fn
+	while (input[ind] != '\0')
+		(student.fn *= 10) += (input[ind++] - '0');
+	
+}
+
+bool saveStudentsToFile(const OOPstudent* studentsCollection, int len, const char* fileName)
+{
+	ofstream outFile(fileName);
+
+	if (!outFile.is_open())
+		return false;
+
+	outFile << "First name, Last name, email, fn" << endl;
+
+	for (int i = 0; i < len; i++)
+		outFile << studentsCollection[i].firstName << "," << studentsCollection[i].lastName << "," << studentsCollection[i].email << "," << studentsCollection[i].fn << endl;
+
+	outFile.close();
+
+	return true;
+}
+
+int indexOfFirstSpaceOrTerminatingZero(const char* command)
+{
+	int ind = 0;
+	while (*command != ' ' && *command != '\t' && *command != '\0')
+	{
+		command++;
+		ind++;
+	}
+	return ind;
+
+}
+
+bool printStudent(const OOPstudent* arrayOfStudents, int len,  int fn)
+{
+	for (int i = 0; i < len; i++)
+	{
+		if (arrayOfStudents[i].fn == fn)
+		{
+			cout << arrayOfStudents[i].firstName << "," << arrayOfStudents[i].lastName << "," << arrayOfStudents[i].email << "," << arrayOfStudents[i].fn << endl;
+			return true;
+		}
+	}
+	return false;
+}
+bool editFirstName(OOPstudent* arrayOfStudents, int len, int fn, const char* newFirstName)
+{
+	for (int i = 0; i < len; i++)
+	{
+		if (arrayOfStudents[i].fn == fn)
+		{
+			strcpy(arrayOfStudents[i].firstName, newFirstName);
+			return true; //success!
+		}
+	}
+	return false; //no such student
+}
+int main()
+{
+
+	cout << "Open file:" << endl << ">";
+
+	char fileName[BUFFER_LINE_SIZE];
+	cin.getline(fileName, BUFFER_LINE_SIZE);
+		
+	int studentsCount = countLines(fileName) - 1; // We ignore the first line 
+
+
+	if (studentsCount <= 0)
+	{
+		cout << "Error while reading data from the file " << endl;
+		return -1;
+	}
+
+	OOPstudent* studentsCollection = new OOPstudent[studentsCount];
+
+
+	ifstream f(fileName, ios::_Nocreate);
+
+	if (!f.is_open())
+	{
+		cout << "Error!" << endl;
+		delete[] studentsCollection;
+		return -1;
+	}
+
+	int line = 1;
+	while (!f.eof())
+	{
+		char buff[BUFFER_LINE_SIZE];
+		f.getline(buff, BUFFER_LINE_SIZE);
+
+		if (line == 1)
+		{
+			line++;
+			continue;
+		}
+
+		readStudent(buff, studentsCollection[line - 2]);
+		line++;
+	}
+	f.close();
+
+	cout << "File successfully opened!" << endl;
+
+	char commandLine[BUFFER_LINE_SIZE];
+	do
+	{
+		cout << ">";
+		cin.getline(commandLine, 1024);
+		size_t len = strlen(commandLine);
+
+
+
+		//first argument (edit, save ...)
+		size_t firstArgSize = indexOfFirstSpaceOrTerminatingZero(commandLine);
+		char* commandFirstArg = new char[firstArgSize + 1];
+
+		for (int i = 0; i < firstArgSize; i++)
+			commandFirstArg[i] = commandLine[i];
+		commandFirstArg[firstArgSize] = '\0';
+
+
+	
+
+		if (len == firstArgSize) //no more arguments - quit? Check is bellow
+			continue;
+
+		//second argument (students.csv, 45543 ...)
+		size_t secondArgSize = len - firstArgSize - 1;
+		char* commandSecondArg = new char[secondArgSize + 1];
+
+		for (int i = 0; i < secondArgSize; i++)
+			commandSecondArg[i] = commandLine[firstArgSize + 1 + i];
+		commandSecondArg[secondArgSize] = '\0';
+		if (strcmp(commandFirstArg, "print") == 0)
+		{
+			int fn = atoi(commandSecondArg);
+
+			bool res = printStudent(studentsCollection, studentsCount, fn);
+
+			if (!res)
+				cout << "Student with fn: " << fn << " doesn't exist!" << endl;;
+		}
+		else if (strcmp(commandFirstArg, "edit") == 0)
+		{
+			int fn = atoi(commandSecondArg);
+
+			//we have a third argument here. It's in the second arguments string
+
+			size_t seprator = indexOfFirstSpaceOrTerminatingZero(commandSecondArg);
+
+			size_t thirdArgumentSize = secondArgSize - seprator;
+			char* commandThirdArg = new char[thirdArgumentSize + 1];
+			
+			for (int i = 0; i < thirdArgumentSize; i++)
+				commandThirdArg[i] = commandSecondArg[seprator + 1 + i];
+			commandThirdArg[thirdArgumentSize] = '\0';
+
+			bool result = editFirstName(studentsCollection, studentsCount, fn, commandThirdArg);
+
+			if (result)
+				cout << "Succesfully changed name!" << endl;
+			else
+				cout << "Student with fn: " << fn << "doesn't exist!" << endl;
+
+			delete[] commandThirdArg;
+		}
+		else if (strcmp(commandFirstArg, "save") == 0)
+		{
+
+			bool res = saveStudentsToFile(studentsCollection, studentsCount, commandSecondArg);
+
+			if (res)
+				cout << "Successfully saved to file: " << commandSecondArg << endl;
+			else
+				cout << "Error while saving in file: " << commandSecondArg << endl;
+
+		}
+		delete[] commandFirstArg;
+		delete[] commandSecondArg;
+
+	} while (strcmp(commandLine, "Quit"));
+
+	delete[] studentsCollection;
+	return 0;
+}