static void Main(string[] args)
{
Calculator1 calc = new Calculator1();
calc.add(20, 30);
calc.difference(30, 20);
calc.division(15, 3);
calc.multiplication(2, 2);
}
public void checkadd()
{
int a = -4;
int b = 4;
int expected = a + b;
int actual = obj.add(a, b);
Assert.AreEqual(actual, expected, 0, "Result is wrong");
int a1 = int.MaxValue;
int b1 = int.MaxValue;
Assert.ThrowsException <System.OverflowException>(() => obj.add(a1, b1));
int a2 = int.MaxValue;
int b2 = 23;
Assert.ThrowsException <System.OverflowException>(() => obj.add(a2, b2));
int a3 = int.MinValue;
int b3 = -2;
Assert.ThrowsException <System.OverflowException>(() => obj.add(a3, b3));
}