include

include

include

using namespace std;
int ID = 0;
struct Student {
int id;
string firstName;
string userName;
string password;
};

void addStudent() {
Student student;
cout << "\n\tEnter First Name : ";
cin.get();
getline(cin, student.firstName); //Nouman Habib
cout << "\n\tEnter User Name : ";
cin >> student.userName;
cout << "\n\tEnter Password : ";
cin >> student.password;

ID++;
student.id = ID;

ofstream write;
write.open("student.txt", ios::app);
write << "\n" << ID;
write << "\n" << student.firstName ;
write << "\n" << student.userName ;

write << "\n" << student.password ;

write.close();
write.open("id.txt");
write << ID;
write.close();
cout << "\n\tData save to file";

}

void print(Student s) {
cout << "\n\t---Stuent Data---";
cout << "\n\tID is : " << s.id;
cout << "\n\tFirst Name is : " << s.firstName;
cout << "\n\tUser Name is : " << s.userName;
cout << "\n\tPassword is : " << s.password;

}

void readData() {
Student student;
ifstream read;
read.open("student.txt");
while (!read.eof()) {
read >> student.id;
read.ignore();
getline(read, student.firstName);
read >> student.userName;
read >> student.password;

    print(student);
}
read.close();

}

int searchData() {
int id;
cout << "\n\tEnter student id want to search : ";
cin >> id;
Student student;
ifstream read;
read.open("student.txt");
while (!read.eof()) {
read >> student.id;
read.ignore();
getline(read, student.firstName);
read >> student.userName;
read >> student.password;

    if (student.id == id) {
        print(student);
        return id;
    }
}

}

void deleteData() {
int id = searchData();
cout << "\n\tYou want to delete record (y/n) : ";
char choice;
cin >> choice;
if (choice == 'y') {
Student student;
ofstream tempFile;
tempFile.open("temp.txt");
ifstream read;
read.open("student.txt");
while (!read.eof()) {
read >> student.id;
read.ignore();
getline(read, student.firstName);
read >> student.userName;
read >> student.password;

        if (student.id != id) {
            tempFile << "\n" << student.id;
            tempFile << "\n" << student.firstName;
            tempFile << "\n" << student.userName;
            tempFile << "\n" << student.password;
        }
    }
    read.close();
    tempFile.close();
    remove("student.txt");
    rename("temp.txt", "student.txt");
    cout << "\n\tData deleted successfuly";
}
else {
    cout << "\n\tRecord not deleted";
}

}

void updateData() {
int id = searchData();
cout << "\n\tYou want to update record (y/n) : ";
char choice;
cin >> choice;
if (choice == 'y') {
Student newData;
cout << "\n\tEnter First Name : ";
cin.get();
getline(cin, newData.firstName);
cout << "\n\tEnter User Name : ";
cin >> newData.userName;
cout << "\n\tEnter Password : ";
cin >> newData.password;

    Student student;
    ofstream tempFile;
    tempFile.open("temp.txt");
    ifstream read;
    read.open("student.txt");
    while (!read.eof()) {
        read >> student.id;
        read.ignore();
        getline(read, student.firstName);
        read >> student.userName;
        read >> student.password;

        if (student.id != id) {
            tempFile << "\n" << student.id;
            tempFile << "\n" << student.firstName;
            tempFile << "\n" << student.userName;
            tempFile << "\n" << student.password;

        }
        else {
            tempFile << "\n"<< student.id;
            tempFile << "\n"<< newData.firstName;
            tempFile << "\n"<< newData.userName;
            tempFile << "\n" << newData.password;

        }
    }
    read.close();
    tempFile.close();
    remove("student.txt");
    rename("temp.txt", "student.txt");
    cout << "\n\tData updated successfuly";
}
else {
    cout << "\n\tRecord not deleted";
}

}

int main()
{
ifstream read;
read.open("id.txt");
if (!read.fail()) {
read >> ID;
}
else {
ID = 0;
}
read.close();

while (true) {
    cout << "\n\t1.Add data";
    cout << "\n\t2.See  data";
    cout << "\n\t3.Search  data";
    cout << "\n\t4.Delete data";
    cout << "\n\t5.Update  data";

    int choice;
    cout << "\n\tEnter choice : ";
    cin >> choice;
    switch (choice) {
    case 1:
        addStudent();
        break;
    case 2:
        readData();
        break;
    case 3:
        searchData();
        break;
    case 4:
        deleteData();
        break;
    case 5:
        updateData();
        break;
    }
}

}

I have created a crud to create, read, update and delete in C++. The problem I am facing right now is that while I enter the data the id's of the person don't start from 1, 2, 3 and so on.

the id's start from the random numbers like 1586 , 1587 and so on

kindly make a run on your compiler you will be able to see the problem at hand.