ساخت یک ماشین حساب ساده در جاوا — از صفر تا صد

1	
2System.out.println("---------------------------------- \n" +
3  "Welcome to Basic Calculator \n" +
4  "----------------------------------");
5System.out.println("Following operations are supported : \n" +
6  "1. Addition (+) \n" +
7  "2. Subtraction (-) \n" +
8  "3. Multiplication (*) \n" +
9  "4. Division (/) \n");

1Scanner scanner = new Scanner(System.in);
2 
3System.out.println("Enter an operator: (+ OR - OR * OR /) ");
4char operation = scanner.next().charAt(0);
5 
6System.out.println("Enter the first number: ");
7double num1 = scanner.nextDouble();
8 
9System.out.println("Enter the second number: ");
10double num2 = scanner.nextDouble();

1if (!(operation == '+' || operation == '-' || operation == '*' || operation == '/')) {
2    System.err.println("Invalid Operator. Please use only + or - or * or /");
3}

1if (operation == '/' && num2 == 0.0) {
2    System.err.println("The second number cannot be zero for division operation.");
3}

1if (operation == '+') {
2    System.out.println(num1 + " + " + num2 + " = " + (num1 + num2));
3} else if (operation == '-') {
4    System.out.println(num1 + " - " + num2 + " = " + (num1 - num2));
5} else if (operation == '*') {
6    System.out.println(num1 + " x " + num2 + " = " + (num1 * num2));
7} else if (operation == '/') {
8    System.out.println(num1 + " / " + num2 + " = " + (num1 / num2));
9} else {
10    System.err.println("Invalid Operator Specified.");
11}

1switch (operation) {
2    case '+':
3        System.out.println(num1 + " + " + num2 + " = " + (num1 + num2));
4        break;
5    case '-':
6        System.out.println(num1 + " - " + num2 + " = " + (num1 - num2));
7        break;
8    case '*':
9        System.out.println(num1 + " x " + num2 + " = " + (num1 * num2));
10        break;
11    case '/':
12        System.out.println(num1 + " / " + num2 + " = " + (num1 / num2));
13        break;
14    default:
15        System.err.println("Invalid Operator Specified.");
16        break;
17}