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#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;
}
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