A small terminal banking app written in C# to emulate some basic functionalities of a banking system

account.txt

user

26/01/98
0000
c
1000

Bank.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.IO;

// A Banking system in C#
//By Tanaka Chinengundu
/*
SO I WROTE THIS CODE AFTER 3 DAYS OF TEACHING MYSELF SOME C#....

I ALREADY HAD SOME PRIOR KNOWLEDGE FROM A COUPLE YEARS BACK
TESTING MY NEW POWERS FROM A PYTHON DEV BACKGROUND
*/

namespace Bank{
	public class CreateAccount{
		private string [] user=new string [6];
		private string user_file = "account.txt";

		public void SetAccount(){
			//Create user Account
			Console.WriteLine("Welcome\nHere you will create your Bank account\nPlease fill out the form\n\n");
			string [] field = new string [6]{"first name:","lest name:","DOD:","password:","account type:","Initial deposit must be >=500\n$:"};

			int controller = 0;
			int max_try = 3; // this is for retrying when user enters deposit < 500
			for(controller=0;controller<6;controller++){
				Console.Write("{0}",field[controller]);
				user[controller] = Console.ReadLine();
			}
			if(Convert.ToInt32(user[5]) < 500){
				Console.WriteLine("Sorry Enter deposit >= 500");
				user[5] = "0.00";
				while(Convert.ToInt32(user[5]) < 500 && max_try > 0){
					Console.Write("{0}",field[5]);
					user[5] = Console.ReadLine(); // Here passing a string because the array is a string array
					max_try--;
				}
			}
			//checking if funds are >= required amount and max_tyr <=0
			// if funds != required amount and max_try <=0 show message
			// then exit
			if(Convert.ToInt32(user[5]) < 500 && max_try <= 0){
					Console.WriteLine("Sorry your account could not be created\n try again later!");
					Console.ReadKey();
				}else{
					if(Convert.ToInt32(user[5]) >= 500){
						Console.WriteLine("Congradulations!!\nYour account has been created successfully");
					}
				}
			//Creating user account file
			if(File.Exists(user_file)){
				try{
					File.WriteAllLines(user_file,user);
				}catch(Exception error){
					Console.WriteLine(error.Message);
				}
			}else{
				try{
					File.WriteAllLines(user_file,user);
				}catch(Exception error){
					Console.WriteLine(error.Message);
				}
			}
		}
	}

	class Account{
		//string user_file = "account.txt";
		private string [] user_info = File.ReadAllLines("account.txt");
		private string [] options = new string[]{"1-> Account Enquiry","2-> Deposit funds","3-> Withdraw funds","4-> Change password"};
		private int opt_view = 0;
		private int limit = 1200;


		public void UserAcount(){
			Console.WriteLine("Login");
			Console.Write("User name:");
			string user_name = Console.ReadLine();
			Console.Write("Password:");
			string password = Console.ReadLine();
			Console.WriteLine("\n\n");

			if(user_name == user_info[0] && password == user_info[3]){
				menu();
			}else{
				Console.WriteLine("Could not login\nWrong credentials!\n{0}\n{1}\n------------------",user_info[0],user_info[3]);
			}
		}

		private int AccountFunds(){
			int funds = Convert.ToInt32(user_info[5]);
			Console.Write("Account Funds\n$:{0}\n\n",funds);
			menu(); //return to main menu
			return funds;
		}
		private void Deposit(){
			//deposit funds to your accounnt
			Console.WriteLine("------------------\nCurrent funds in account:\n$ {0}\n---------------------\n",user_info[5]);
			Console.Write("Deposit amount:$ ");
			string funds = Console.ReadLine();
			if(Convert.ToInt32(funds) > 0 ){
				try{
					if(File.Exists("account.txt")){
						int new_funds = Convert.ToInt32(user_info[5]) + Convert.ToInt32(funds);
						try{
							user_info[5] = Convert.ToString(new_funds);
							File.WriteAllLines("account.txt",user_info);
						}catch(Exception error){
							Console.WriteLine(error.Message);
						}
					}
				}catch(Exception error){
					Console.WriteLine("------------------------\n{0}\n---------------------",error.Message);
				}
			}else{
				Console.WriteLine("-----------------------\nEnter amount > 0");
			}
			Console.WriteLine("Your funds have deposited successfully!");
			Console.WriteLine("New ballance:\n$ {0}\n",user_info[5]);
			menu();
		}

		private void Withdraw(){
			Console.WriteLine("----------------------------------");
			Console.WriteLine("Current funds:$ {0}\nLimit:$ {1}",user_info[5],limit);
			Console.WriteLine("----------------------------------");
			int current_funds = Convert.ToInt32(user_info[5]);

			Console.Write("Withdraw:$ ");
			int withdraw = Convert.ToInt32(Console.ReadLine());

			if(withdraw < limit && Convert.ToInt32(user_info[5]) - withdraw > 0){
				int new_funds = current_funds - withdraw;
				user_info[5] = Convert.ToString(new_funds);
				try{
					File.WriteAllLines("account.txt",user_info);
				}catch(Exception error){
					Console.WriteLine(error.Message);
				}
			}else{
				Console.Write("--------------------------------------\n");
				Console.WriteLine("Your request is above the limit\nRequest:$ {0}\nCurrent balance:$ {1}\nLimit:$ {2}",withdraw,user_info[5],limit);
				Console.Write("--------------------------------------\n\n");
				withdraw = 0; //reseting request
				Withdraw();
			}
			Console.WriteLine("Funds successfully withdrawn!\nNew Account ballance:$ {0}\n\n",user_info[5]);
			menu();
		}

		private void ChangePassword(){
			Console.Write("Change your password here\nKeep your password safe\n\n");
			string current_password = user_info[3];
			Console.Write("Confirm old password: ");
			string confirm = Console.ReadLine();
			if(confirm == current_password){
				Console.Write("\nEnter new password: ");
				string password = Console.ReadLine();
				if(password != current_password){
					user_info[3] = password;
				}else{
					Console.Write("------------------------------------------------\n");
					Console.Write("New password can not be the same as old password\n");
					Console.Write("--------------------------------------------------\n");
					ChangePassword();
				}
			}else{
				Console.Write("\n----------------\nPassword mismatched\n--------------------\n");
				ChangePassword();
			}
			try{
				File.WriteAllLines("account.txt",user_info);
			}catch(Exception error){
				Console.WriteLine(error.Message);
			}
			Console.WriteLine("Your password has been changed successfully!\n");
			menu();
		}


		public void menu(){
			//Account Main Menu
			for(opt_view=0;opt_view<4;opt_view++){
					Console.WriteLine("{0}",options[opt_view]);
				}
			Console.Write(">>");
			string option = Console.ReadLine();
			if(Convert.ToInt32(option) == 1){
				AccountFunds();
			}else{
				if(Convert.ToInt32(option) == 2){
					Deposit();
				}
			}
			if(Convert.ToInt32(option) == 3){
					Withdraw();
				}
			if(Convert.ToInt32(option) == 4){
					ChangePassword();
				}
		}
	}

	class Run{
		static void Main(String [] args){
			Console.Title = "Bank";
			CreateAccount signup = new CreateAccount();
			Account user = new Account();
			Console.Write("\n\n1-> login\n2->Register\n>>");
			int option = Convert.ToInt32(Console.ReadLine());
			if(option == 1){
				user.UserAcount();
			}else{
				signup.SetAccount();
			}
			Console.ReadKey();
		}
	}
}