import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Main {

public static void main(String[] args) throws SQLException {
Scanner sc = new Scanner(System.in);
Connection conn = null;
PreparedStatement pstmt = null;

try {
Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521", "scott", "tiger");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}

int rollno = 0;
do {
System.out.print("Enter rollno: ");
String rollstr = sc.nextLine();

try {
rollno = Integer.parseInt(rollstr);
if (String.valueOf(rollno).length() != 4) rollno = 0;
} catch (Exception e) {}
} while (rollno == 0);

String studentName = "";
boolean lowercasefound;
do {
System.out.print("Enter name: ");
studentName = sc.nextLine();

lowercasefound = false;
for (int i = 0; i < studentName.length(); i++) {
if (Character.isLowerCase(studentName.charAt(i))) {
lowercasefound = true;
break;
}
}

} while (studentName.length() > 20 || lowercasefound);

String standard = "";
String[] standards = {"I", "II", "III", "IV", "V", "Vi", "VII", "VIII", "IX", "X"};
List<String> list = new ArrayList<>(Arrays.asList(standards));
do {
System.out.print("Enter standard: ");
standard = sc.nextLine();
} while (!list.contains(standard));



// inserting data into db
String sql = "INSERT INTO stdnt VALUES(?, ?, ?)";
try {
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, rollno);
pstmt.setString(2, studentName);
pstmt.setString(3, standard);

pstmt.executeQuery();
System.out.println("Student added successfully");
} catch (SQLException e) {
e.printStackTrace();
System.out.println("Error");
pstmt.close();
conn.close();
} 

sc.close();
}

}