Page 121 - CA_Blue( J )_Class9
P. 121

06


                                                                             INPUT IN JAVA
















                           Learning Objectives



                     6.1 Comments in Java                                6.2 Packages in Java
                     6.3 Initialisation                                  6.4 Input using Parameters
                     6.5 Using Scanner Class                             6.6 Using InputStreamReader Class
                     6.7 Errors in Java                                  6.8 Testing and Debugging
                     6.9 Exception Handling in Java





                 So far you have learnt about programming in Java with simple examples. In this chapter, we are going to learn
                 about the input and exception handling in Java.


                     6.1 COMMENTS IN JAVA
                 While writing a program code, we might need to explain certain parts of the program. This helps us to understand
                 the reason for writing the statements. This can be done with the help of comments. Comments are non-executable
                 statements that are required to explain certain parts of the program or add notes to some parts of the program.
                 This also helps a new programmer to debug any error easily.
                 In  Java, there are three  types of  comments: single-line comments, multi-line  comments and  documentation
                 comments. Let us learn about them in detail.

                 6.1.1 Single-line Comments
                 These comments are used to write one-line comments. It may be written in a new line or after the end of the
                 statement, i.e., after the semicolon (“;”). A single-line comment begins with “//” (double forward slash). For example,


                 //The below statement prints My book name is Touchpad
                 System.out.println(“My book name is Touchpad”);

                 6.1.2 Multiline Comments
                 These comments are used to write more than one line or multiple lines so that the logic of the code can be
                 explained in detail. They begin with “/*” and end with “*/”.

                 /*This program code prints whether the numbers 5 and 2 are equal or not. If they are
                 equal, it will print Equal; otherwise, it will print Not Equal.*./


                                                                                                   Input in Java   119
   116   117   118   119   120   121   122   123   124   125   126