Thread: Can you help me to make this calculator better

package com.company;

import javax.swing.*;

class Calculator {
static void Addition() {
Float sum = Float.parseFloat(JOptionPane.showInputDialog("Ente r First value:-"));
Float sum2 = Float.parseFloat(JOptionPane.showInputDialog("Ente r second value"));
Float answer = sum + sum2;
System.out.println("\nThis is your answer:-");
System.out.println("\n " + answer);
}

static void Subtraction() {
Float sub = Float.parseFloat(JOptionPane.showInputDialog("Ente r First value:-"));
Float sub2 = Float.parseFloat(JOptionPane.showInputDialog("Ente r second value:-"));
Float answer = sub - sub2;
System.out.println("\nThis is your Answer:-");
System.out.println("\n " + answer);
}

static void Multiplication() {
Float mul = Float.parseFloat(JOptionPane.showInputDialog("Ente r first value:-"));
Float mul2 = Float.parseFloat(JOptionPane.showInputDialog("Ente r second value:-"));
Float answer = mul * mul2;
System.out.println("\nThis is your answer:-");
System.out.println(" " + answer);
}

static void Division() {
Float div = Float.parseFloat(JOptionPane.showInputDialog("Ente r first value:-"));
Float div2 = Float.parseFloat(JOptionPane.showInputDialog("Ente r second value"));
Float answer = div / div2;
System.out.println("\nThis is your answer:-");
System.out.println("\n " + answer);
}

static void exponents(){
Float base = Float.parseFloat(JOptionPane.showInputDialog("Ente r base:-"));
Float power = Float.parseFloat(JOptionPane.showInputDialog("Ente r power:-"));
double answer = Math.pow(base,power);
System.out.println("\nThis is your answer:-");
System.out.println(" "+answer);
}
static void percentage(){
Float number = Float.parseFloat(JOptionPane.showInputDialog("Ente r number:-"));
Float percentage = Float.parseFloat(JOptionPane.showInputDialog("Ente r percentage you want to calculate:-"));
Float total = 1/100F*percentage;
Float total2 = total*number;
System.out.println("\nThis is your answer:-");
System.out.println(" "+total2);
}
static void sum_of_factors(){
int n = Integer.parseInt(JOptionPane.showInputDialog("Plea se enter a number to find sum of divisors:-"));
int i,sum = 0;
for (i=1;i<=n;i++)
{
if (n%i==0) {
sum = sum+i;

}

}
System.out.println("Sum of divisors of "+n+" = "+sum);
}
static void product_of_divisors(){
int n = Integer.parseInt(JOptionPane.showInputDialog("Ente r a number to find product of divisors"));
int i,product = 1;
for (i = 1;i<=n;i++){
if (n%i==0){
product = product*i;
}
}
System.out.println("Product of divisors of "+n+" = "+product);
}
public static void main(String[]args){
String arthimeticoperation;
char selection;

System.out.println("Possible arithmetic operations:-\n a addition \n b subtraction \n c Multiplication \n d Division \n e Exponents \n f percentage \n g sum of divisors of numbers \n h product of divisors");
arthimeticoperation = JOptionPane.showInputDialog("What would you like to initiate?:-");
selection = arthimeticoperation.charAt(0);
switch (selection){
case 'a':
Addition();
break;
case 'b':
Subtraction();
break;
case 'c':
Multiplication();
break;
case 'd':
Division();
break;
case 'e':
exponents();
break;
case 'f':
percentage();
break;
case 'g':
sum_of_factors();
break;
case 'h':
product_of_divisors();
break;
default:
System.out.println("Please enter a valid variable");
break;
}

}
}

package com.company;

import javax.swing.*;

class ATM{
static void Balance(){
String restart = "Y";
Float balance = 77000.54F;
System.out.println("This is you Balance:- "+balance);
restart = String.join(JOptionPane.showInputDialog("Would you like to go back?));
if (restart == "no") {
System.out.println("Thank you");
}
}
static void withdrawl(){
Float balance = 77000.54F;
Float withdrawl = Float.parseFloat(JOptionPane.showInputDialog("How much do you want to withdraw?:- "));
if (withdrawl <= balance){
balance = balance - withdrawl;
System.out.println("\nNow,This is your Balance:- "+balance);
}else{
System.out.println("\nPlease enter desired amount");
}
}
static void Pay_in(){
Float balance = 77000.54F;
Float Pay_in = Float.parseFloat(JOptionPane.showInputDialog("\nHo w much do you want to Pay in?));
if (Pay_in == Pay_in){
balance = balance + Pay_in;
System.out.println("Now,This is your balance:- "+balance);
}else {
System.out.println("\nPlease enter a desired amount);
}
}
static void return_card(){
System.out.println("Please wait while your card is returned");
System.out.println("Thank you for your service");
}
public static void main(String[]args){
int chances = 4;
while (chances >= 0){
System.out.println("Welcome to Bank of America");
Integer pin = Integer.parseInt(JOptionPane.showInputDialog("Plea se enter your 4 digit pin));
if (pin == 1234){
System.out.println("Congratulations you have entered your pin sucessfully");
String options;
char selection;
System.out.println("\nPress 1 to see your Balance \nPress 2 to Withdrawl \nPress 3 to Pay in \nPress 4 to return card");
options = JOptionPane.showInputDialog("\nWhat would you like to choose);
selection = options.charAt(0);

switch (selection){
case '1':
Balance();
break;
case '2':
withdrawl();
break;
case '3':
Pay_in();
break;
case '4':
return_card();
break;
default:
System.out.println("Please enter a valid option");
}
}else {
System.out.println("Incorrect pin please try again");
chances = chances - 1;
if (chances == 3) {
System.out.println("3 more tries");
}else if (chances == 2){
System.out.println("2 more tries");
}else if (chances == 1){
System.out.println("This is your last try");
}
}
}
}
}