Just as you can pass primitive type values to methods, you can also pass arrays to a method. To pass an array to a method, specify the name of the array without any square brackets within the method call. Unlike C/C++, in Java every array object knows its own length using its length field, therefore while passing array's object reference into a method, we do not need to pass the array length as an additional argument. For example: Suppose we have an integer array num containing 10 elements.
With the release of version 1.5, Java introduced a new type of for loop known as enhanced or numerical for loop. It is designed to simplify loops that process elements of array or collection.It is useful when you want to access all the elements of an array but if you want to process only part of the array or modify the values in the array then use the simple for loop.
Just like simple variables can store different values at different times, an array variable can also be used to store a reference to different arrays at different times. Suppose you have created and initialized array variable num using the following statement,
After you create an array, you can access its length i.e. number of elements it holds. You can refer to the length of an array using its length field (which is implicitly public and final).A length field is associated with each array that has been instantiated. Because length field is a public member so it can be directly accessed using the array name and a dot operator. Its syntax is
When an array is created, each element of the array is set to default initial value according to its type. However, it is also possible to provide value other than the default values to each element of the array.
Once the array is created, you can access an array element by using the name of the array followed by an index enclosed between a pair of square brackets. The index or subscript of an array indicates the position of an element in the array. The index of the first element in the array is always 0 (zero), the second element has an index 1 and so on. The index of the last element is always one less than the number of elements in the array. The syntax for accessing an array element is
Just like one-dimensional arrays, a two-dimensional array can also be passed to a method and it can also be returned from the method. The syntax is similar to one-dimensional arrays with an exception that an additional pair of square brackets is used. Two-dimensional Array is specified by taking additional square brackets i.e. "".
StringBuffer reverse () : This method reverse the character sequence contained in the string buffer. In other words, the first character becomes the last, the second character becomes the second last and so on. For example, The Word “welcome” after reverse.
charAt():- This is a predefined method of String class present in java.1ang package. It used to extract a specify character from a string by the particular index supplied by the programmer and the index must be within the length of the String.
Dinesh Thakur holds an B.C.A, MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular Computer Notes blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.