Scan Number Field with airSlate SignNow

Scan number field

this video is just a short extract from the entire course if you wish to see all of the videos from this series at higher quality and in far larger screen size head over to eye F skills calm in this lesson we're going to learn how to retrieve input from the user at the keyboard this has lots of uses both practical and real-world in that you cannot constantly be assigning data in your programs you need to be able to ask the user to enter data and have the program store the data that the user types at the keyboard and in real-world programs you're not going to be assigning data all the time anyway you're going to be getting input from the user so learning how to do this is quite important to get input from the user at the keyboard we have to import a class called the scanner class and importing involves writing a line of code at the beginning of the program at the very top above the public class where you type the keyword import followed by the name of the class in which case we went the scanner class and notice I didn't just write import scanner I wrote import java.util.scanner Java dot util is a package where the scanner class is located by putting classes in packages we can use method names and other identifier names over and over again without causing any conflicts so the different classes that make up the libraries of java are all located in different packages and the scanner class this happens to be located in Java util once we've imported the scanner class we're ready to actually create a scanner object and that's how we get input from the user we create an object of the scanner class and then use that to get the input so to do that we're going to declare a new object we'll call it input and then we call the constructor for the scanner class and what the constructor wants is a input object in this case the keyboard which is represented by system dot in you've seen how Java represents the screen by a system dot out well the keyboard is represented by system dot in so by writing this line of code scanner input equals new scanner system in we're saying that we want to associate the object input with the keyboard now we're ready to get some data let's first create a integer variable number then let's retrieve that number from the keyboard the way we do that is we write a method from the input object called next int what happens is when the compiler comes across the sign of code when it sees next int it stops the program and lets the user enter a number at the keyboard press ENTER and then at that point that input is assigned to the variable on the left hand side of the assignment statement so we can verify that that works by having a system out line right here or we'll just echo the number back out so let's save and run this program and see what we get then we compile it at seven part three not Calva and then run it I didn't put a prompt in here so we're just going to enter a number my prompt it probably would have been a little bit better so we'd type in 45 and then it goes back the number is 45 why don't we do this let's just go ahead and write a real simple little addition program we're going to create two integer variables then we're going to now let's create a sum variable also to store the sum now let's prompt the user system out dot print enter the first number then get the number with input dot next int then we're going to prompt the user to enter the second number number one gets the next energy entered like so and we can compute the sum number plus number one and then we can write out system.out.print line the sum is I won't put the numbers back up there and then we can just delete this last line like so the program Pyle again and then run it so we'll do 23 the second number will be 56 the Sun is 79 can work with floating-point numbers just as easily as we work with integers simply by changing the method that we retrieve numbers with so if I want to do a double addition program all I've got to do is change my declaration to doubles and then change the method from next int your next double like so and that's all we have to do save the program now let's compile and run it will enter a 0.34 and 2.56 and it says the sum is 2.9 you can also mix data types using the input object just like you can an assignment you just have to be careful you can assign integer values to double variables using next int into a double but you cannot assign next double inputs into an integer because of the loss of precision so the same rules that apply to doing mixed math in Java also applied to entering numbers into variables in mixed ways so you can put an integer into a double but you can't put a double into an integer so to review the key to getting input from the user is to import the scanner class be sure to set up a input object it doesn't have to be called input that's just a variable name but some object that is associated with system dot in using the scanner class in its constructor and then calling the appropriate method either next int or next double to retrieve the number from the keyboard so that explains how to get new American put from the keyboard and then my next lesson we're going to learn how to get string input from the keyboard