Welcome to this course, Java as a Second Language. This is Module 1. And here are our operators for integers, so this is exactly the same as C and C++. We have are less than or equal to, our less than. Again, our quality is the double equals, equals for inequality. Greater than or equal to and greater than. In our arithmetic operators, not only are they equivalent or identical to C and C++, but to many other programming languages. Obviously, we have our addition, subtraction, multiplication, division, modulo. So if we want to divide and work with the remainder and then exponential. So if we take a quick look here, we can see assignment, and we can see some arithmetic operations and some concatenation. We can see here this string which we'll talk about string shortly, comes from the top of this method. This method actually returns a string. That's why we see this return statement down here, but we can see assignment here. So myGreet is being assigned the value of greet. And we can see here these two integers, my_intx and My_inty are being assigned what the integers that are coming in here is parameters. And then the sum which has also to be an integer. We're adding these two, and the sum of these two integers, and then we can see it's all returned here at interestingly as a string. because this is a concatenation symbol as well, so the + sign is what we call overloaded. We'll talk about overloading a little bit later on. We can see here the + sign is being used to some two integers, but it's also being used for concatenation both ways, and it's the way it's used or the context that it's used. That's how Java knows how to use overloaded operators. Strings are, they are not primitive data, but they are special classes. Again, they're not primitive, so classes are always have to be inside quotes. A double quotes or single quotes. Strings can be compared. They do have special properties and methods for comparison, so you can see if they are equivalent or not equivalent. And they also there are escape characters as well, so similar to C and C++, the new line, the tab. Many others, it's the backslash and then the escape character. Dates the same thing. Dates is a class. It's not a type of primitive data, so a day class will take its base, which is the epoch. That's the number of seconds, since a certain certain date and time, and it will take those number of seconds and format that in a number of ways. Dates can be compared. So, we can see here that we're actually instantiating the date class the dt, and we can output, we can get some output here from dt, we're converting it to a string there. And we're out putting to the console. You can see the output here. So again, since it is a class that has a number of properties and methods that we can use. Then we can see here operators for our strings, for our dates. Again concatenations the + sign, we can update a string by using the +=. That's sometimes that's considered shorthand. We can look for equality, and the equality sometimes has to be done through methods or properties. And inequality as well, same thing there could be times where we have to we cannot use the operators. We may have to use methods and properties. And we can see here for data operators, we can format, notice here we're passing in a format. This is again very, very similar to C and C++. We can haul on our date before method, and after method or equals method. And you can see here that again we are putting out and after, we're declaring or determining a base date here. And we're checking to see if it becomes after, and in this case it looks like it is true that today's date is after January 1st, 2020. So based day is probably today's date [LAUGH]. Looks like that's what's going on here, and we're able to do that test. And well, this is interesting too. So for formatting of dates or for calculating dates, we're actually using a try catch block here, which will see a little bit later. But you can see here, we're declaring a new date or instantiating a date using baseDt. And then were able to parse a certain character string. In this case, it looks like we're trying to say 20200101, so that's January 1st, 2020, we're formatting it in a certain way. And then we're out putting that. And notice we are using a try catch block, because, well, we could, it is possible to send in a string here that cannot be parsed to a date field. So, if we had said 2020, we put in a 15, right? There are no 15 months and maybe a 40 right, here that would throw an exception. And we'll talk a little bit about that coming up.
