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1. Top results related to declare int array in java

   • int array to int number in Java

     Top Answer

     Answered Jan 28, 2014 · 18 votes

     Start with a result of 0. Loop through all elements of your int array. Multiply the result by 10, then add in the current number from the array. At the end of the loop, you have your result.

     • Result: 0
     • Loop 1: Result * 10 => 0, Result + 1 => 1
     • Loop 2: Result * 10 => 10, Result + 2 => 12
     • Loop 3: Result * 10 >= 120, Result + 3 => 123

     This can be generalized for any base by changing the base from 10 (here) to something else, such as 16 for hexadecimal.

     Other Answers

     Answered Jan 28, 2014 · 6 votes

     You have to cycle in the array and add the right value. The right value is the current element in the array multiplied by 10^position.

     So: ar[0]*1 + ar[1]*10 + ar[2] *100 + .....

     int res=0; for(int i=0;i<ar.length;i++) { res=res*10+ar[i]; }-

     Or

     for(int i=0,exp=ar.length-1;i<ar.length;i++,exp--) res+=ar[i]*Math.pow(10, exp);-

     Other Answers

     Answered Sep 23, 2015 · 4 votes

     First you'll have to convert every number to a string, then concatenate the strings and parse it back into an integer. Here's one implementation:

     int arrayToInt(int[] arr){ //using a Stringbuilder is much more efficient than just using += on a String. //if this confuses you, just use a String and write += instead of append. StringBuilder s = new StringBuilder(); - for (int i : arr) { s.append(i); //add all the ints to a string }- return Integer.parseInt(s.toString()); //parse integer out of the string}-

     Note that this produce an error if any of the values past the first one in your array as negative, as the minus signs will interfere with the parsing.

     This method should work for all positive integers, but if you know that all of the values in the array will only be one digit long (as they are in your example), you can avoid string operations altogether and just use basic math:

     int arrayToInt(int[] arr){ int result = 0;- //iterate backwards through the array so we start with least significant digits for (int n = arr.length - 1, i = 1; n >= 0; n --, i *= 10) { result += Math.abs(arr[n]) * i; }- if (arr[0] < 0) //if there's a negative sign in the beginning, flip the sign { result = - result; }- return result;}-

     This version won't produce an error if any of the values past the first are negative, but it will produce strange results.

     There is no builtin function to do this because the values of an array typically represent distinct numbers, rather than digits in a number.

     EDIT:

     In response to your comments, try this version to deal with longs:

     long arrayToLong(int[] arr){ StringBuilder s = new StringBuilder(); - for (int i : arr) { s.append(i); }- return Long.parseLong(s.toString());}-

     Edit 2:

     In response to your second comment:

     int[] longToIntArray(long l){ String s = String.valueOf(l); //expand number into a string- String token;- int[] result = new int[s.length() / 2]; - for (int n = 0; n < s.length()/2; n ++) //loop through and split the string { token = s.substring(n*2, (n+2)*2); result[n] = Integer.parseInt(token); //fill the array with the numbers we parse from the sections }- return result;}-

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     1/5

   • Declare an array in java without size

     Top Answer

     Answered Jun 21, 2016 · 34 votes

     There is a NullPointerException because you declared but never initialized the array.

     You can dynamically declare an array as shown below.

     int size = 5; // or anyother value you want int[] array = new int[size];-

     Or you use a list. Which allows to dynamically change the size. E.g:

     List<Integer> list = new ArrayList<>(); list.add(5); //adds number 5 to the list int number = list.get(0); // Returns Element which is located at position 0 (so in this example in number will be "5");-

     Check all answers on Stack Overflow

     2/5

   • Int and Double in one array in Java

     Top Answer

     Answered Sep 11, 2010 · 2 votes

     You can do this by having an array of objects that are superclasses of Integer/Double (as pointed out elsewhere).

     However I would perhaps enforce type safety by implementing an object that has an Integer component plus an array of Doubles, and store an array of these. The upside (despite the additional complexity) is that you'll have type safety and not have to cast the first element to an Integer whilst casting the remainder to Doubles.

     Check all answers on Stack Overflow

     3/5

   • Declare and initialize an array in Java

     Top Answer

     Answered Jan 05, 2013 · 9 votes

     Initialize it in a static block, of course:

     static { str st[] = new str[10]; for (int i = 0; i < st.length; ++i) { st[i] = new str(); }}

     Everyone else is assuming that your str means java.lang.String. I'm not.

     I'll point out that your naming and coding conventions are rather poor. I'd recommend following the Java coding standards and thinking harder about good names for things.

     Check all answers on Stack Overflow

     4/5

   • Declare Initial Value of BigDecimal Array in Java

     Top Answer

     Answered Dec 19, 2013 · 20 votes

     I would use Arrays.fill() as that will would for any number of zeros (or any other BigDecimal value you like) This works because BigDecimal is immutable, don't do this for mutable values ;)

     BigDecimal[] val = new BigDecimal[N];Arrays.fill(val, BigDecimal.ZERO);-

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     5/5

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2. stackoverflow.com · questions · 1200621How do I declare and initialize an array in Java? - Stack ...

   stackoverflow.com · questions · 1200621

   

   Jul 29, 2009 · There are several ways to declare and int array: int[] i = new int[capacity]; int[] i = new int[] {value1, value2, value3, etc}; int[] i = {value1, value2, value3, etc}; where in all of these, you can use int i[] instead of int[] i. With reflection, you can use (Type[]) Array.newInstance(Type.class, capacity);

3. Searches related to declare int array in java

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4. www.geeksforgeeks.org · arrays-in-javaArrays in Java - GeeksforGeeks

   www.geeksforgeeks.org · arrays-in-java

   

   • Basics of Arrays in Java
   • Arrays in Java
   • Creating, Initializing, and Accessing An Arraysin Java
   • Instantiating An Array in Java
   • Array Literal in Java
   • Multidimensional Arrays in Java
   • Passing Arrays to Methods
   • Returning Arrays from Methods
   • Class Objects For Arrays
   • Java Array Members

   Array Declaration

   To declare an array in Java, use the following syntax: 1. type: The data type of the array elements (e.g., int, String). 2. arrayName: The name of the array.

   Create an Array

   To create an array, you need to allocate memory for it using the newkeyword: 1. This statement initializes the numbersarray to hold 5 integers. The default value for each element is 0.

   Access an Element of an Array

   We can access array elements using their index, which starts from 0: 1. The first line sets the value of the first element to 10. The second line retrieves the value of the first element.

   See full list on geeksforgeeks.org

   In Java, all arrays are dynamically allocated.

   Arrays may be stored in contiguous memory[consecutive memory locations].

   Since arrays are objects in Java, we can find their length using the object property length. This is different from C/C++, where we find length using size of.

   A Java array variable can also be declared like other variables with after the data type.

   See full list on geeksforgeeks.org

   The general form of array declaration is 1. An array declaration has two components: the type and the name. 2. typedeclares the element type of the array. 3. The element type determines the data type of each element that comprises the array. 4. Like an array of integers, we can also create an array of other primitive data types like char, float, do...

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   When an array is declared, only a reference of an array is created. To create or give memory to the array, you create an array like this: The general form of newas it applies to one-dimensional arrays appears as follows: Here, typespecifies the type of data being allocated, sizedetermines the number of elements in the array, and var-nameis the name...

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   In a situation where the size of the array and variables of the array are already known, array literals can be used. 1. The length of this array determines the length of the created array. 2. There is no need to write the new int part in the latest versions of Java.

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   Multidimensional arrays are arrays of arrayswith each element of the array holding the reference of other arrays. These are also known as Jagged Arrays. A multidimensional array is created by appending one set of square brackets () per dimension.

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   Like variables, we can also pass arrays to methods. For example, the below program passes the array to method sumto calculate the sum of the array’s values.

   See full list on geeksforgeeks.org

   As usual, a method can also return an array. For example, the below program returns an array from method m1.

   See full list on geeksforgeeks.org

   Every array has an associated Class object, shared with all other arrays with the same component type.

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   Now, as you know that arrays are objects of a class, and a direct superclass of arrays is a class Object. The members of an array type are all of the following: 1. The public final field lengthcontains the number of components of the array. Length may be positive or zero. 2. All the members are inherited from class Object; the only method of Object...

   See full list on geeksforgeeks.org

   • Video Duration: 9 min

5. www.geeksforgeeks.org · how-to-initialize-an-arrayHow to Initialize an Array in Java? - GeeksforGeeks

   www.geeksforgeeks.org · how-to-initialize-an-array

   

   May 14, 2023 · In Java, an array can be initialized by default values when the size of the array is declared with rectangular brackets [ ]. int [] arr = new int[20]; In the above code, an array of size 20 is declared where the data type is integer.

6. www.w3schools.com · java · java_arraysJava Arrays - W3Schools

   www.w3schools.com · java · java_arrays

   

   To create an array of integers, you could write: int[] myNum = {10, 20, 30, 40}; Access the Elements of an Array. You can access an array element by referring to the index number. This statement accesses the value of the first element in cars: Example.

7. stackabuse.com · how-to-declare-and-initialize-anHow to Declare and Initialize an Array in Java - Stack Abuse

   stackabuse.com · how-to-declare-and-initialize-an

   

   Sep 20, 2022 · In this article, we'll go over how to declare and initialize an array in Java, with examples and best practices. We'll cover traditional array declaration and initialization, as well as IntStreams.

8. www.baeldung.com · java-initialize-arrayInitializing Arrays in Java - Baeldung

   www.baeldung.com · java-initialize-array

   

   Jun 26, 2024 · We can easily declare an array by specifying its data type followed by square brackets and the array name: int[] numbers; In the code above, we declare an uninitialized array of int type. Alternatively, we can place the square brackets after the array name, but this approach is less common: int numbers[];

9. People also ask

   How to declare an array in JavaScript?

   • We can easily declare an array by specifying its data type followed by square brackets and the array name: In the code above, we declare an uninitialized array of int type. Alternatively, we can place the square brackets after the array name, but this approach is less common: Furthermore, we must initialize an array to use it.

   Initializing Arrays in Java - Baeldung

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   What is array type in Java?

   • type declares the element type of the array. The element type determines the data type of each element that comprises the array. Like an array of integers, we can also create an array of other primitive data types like char, float, double, etc., or user-defined data types (objects of a class).

   Arrays in Java - GeeksforGeeks

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   How to initialize an array in Java?

   • We can initialize an array with default or non-default values. Below are different methods to initialize an Array: In Java, an array can be initialized by default values when the size of the array is declared with rectangular brackets [ ]. In the above code, an array of size 20 is declared where the data type is integer.

   How to Initialize an Array in Java? - GeeksforGeeks

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   What is int array in JavaScript?

   • Although the first declaration establishes that int Array is an array variable, no actual array exists. It merely tells the compiler that this variable (int Array) will hold an array of the integer type. To link int Array with an actual, physical array of integers, you must allocate one using new and assign it to int Array.

   Arrays in Java - GeeksforGeeks

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10. www.programiz.com · java-programming · arraysJava Array (With Examples) - Programiz

    www.programiz.com · java-programming · arrays

    

    How to declare an array in Java? In Java, here is how we can declare an array. dataType[] arrayName; dataType - it can be primitive data types like int, char, double, byte, etc. or Java objects; arrayName - it is an identifier; For example, double[] data; Here, data is an array that can hold values of type double. But, how many elements can ...