CRUD.java

import java.util.Scanner;

public class CRUD {
    static Scanner scan = new Scanner(System.in);
    static String[] nama = new String[100];
    static String[] nim = new String[100];
    static String[] kelas = new String[100];
    static int count = 0;
    public static void main(String[] args) {
        int pilihan;
        do {
            System.out.println("Kita akan membuat sistem CRUD");
            System.out.println("1. Create\n2. Show\n3. Update\n4. Delete\n5. Exit\n");
            System.out.print("Input pilihan untuk melanjutkan : ");
            pilihan = scan.nextInt();
            scan.nextLine();
            switch (pilihan){
                case 1:
                    create();
                    break;
                case 2:
                    show();
                    break;
                case 3:
                    update();
                    break;
                case 4:
                    delete();
                    break;
                case 5:
                    System.out.println("Terima kasih!!");
                    break;
                default:
                    System.out.println("Input tidak valid!!");
                    break;
            }
        } while (pilihan != 5);
    }

    static void create(){
        //membuat data
        count++;
        System.out.print("Masukkan nama anda : ");
        nama[count] = scan.nextLine();
        System.out.print("Masukkan NIM anda : ");
        nim[count] = scan.nextLine();
        System.out.print("Masukkan Kelas anda : ");
        kelas[count] = scan.nextLine();
        System.out.println();
    }

    static void show(){
        //mengoutput seluruh data
        if (count == 0){
            System.out.println("Nothing to show");
        } else {
            int a = 1;
            while(a <= count){
                System.out.println("Data " + a);
                System.out.printf("%10s %1s %-20s\n", "Nama anda", ":", nama[a]);
                System.out.printf("%10s %1s %-20s\n", "NIM anda", ":", nim[a]);
                System.out.printf("%10s %1s %-20s\n\n", "Kelas anda", ":", kelas[a]);
                a++;
            }
        }
        System.out.println();
    }

    static void update(){
        //mengupdate isi array berdasarkan data pilihan user
        if (count == 0){
            System.out.println("Nothing to update");
        } else {
            System.out.print("Masukkan nomor data yang ingin di update : ");
            int pilihan = scan.nextInt();
            scan.nextLine();
            System.out.print("Nama (baru) anda : ");
            nama[pilihan] = scan.nextLine();
            System.out.print("NIM (baru) anda : ");
            nim[pilihan] = scan.nextLine();
            System.out.print("Kelas (baru) anda : ");
            kelas[pilihan] = scan.nextLine();
        }
        System.out.println();
    }

    static void delete(){
        //menghapus data array berdasarkan pilihan user
        if (count == 0){
            System.out.println("Nothing to delete");
        } else {
            System.out.print("Masukkan nomor data yang ingin dihapus : ");
            int pilihan = scan.nextInt();
            nama[pilihan] = "";
            nim[pilihan] = "";
            kelas[pilihan] = "";
        }
        System.out.println();
    }
}