Found 9326 Articles for Object Oriented Programming

Let’s say we have the following string, that has some letters and numbers.String str = "9as78";Now loop through the length of this string and use the Character.isLetter() method. Within that, use the charAt() method to check for each character/ number in the string.for (int i = 0; i < str.length(); i++) {    if (Character.isLetter(str.charAt(i)))    count++; }We have set a count variable above to get the length of the letters in the string.Here’s the complete example.Example Live Demopublic class Demo {    public static void main(String []args) {       String str = "9as78";       int count ... Read More

To check whether the entered value is a letter or not in Java, use the Character.isLetter() method.We have a value to be checked.char val = 'D';Now let us use the Character.isLetter() method.if (Character.isLetter(val)) {    System.out.println("Character is in Lowercase!"); }else {    System.out.println("Character is in Uppercase!"); }Let us see the complete example now to check for letter.Example Live Demopublic class Demo {    public static void main(String []args) {       System.out.println("Checking whether the given value is a Letter or not...");       char val = 'D';       System.out.println("Value: "+val);       if (Character.isLetter(val)) {   ... Read More

To validate if a String has only numbers, you can try the following codes. We have used the matches() method in Java here to check for number in a string.Example Live Demopublic class Demo {    public static void main(String []args) {       String str = "978";       System.out.println("Checking for string that has only numbers...");       System.out.println("String: "+str);       if(str.matches("[0-9]+") && str.length() > 2)       System.out.println("String has only numbers!");       else       System.out.println("String consist of characters as well!");    } }OutputChecking for string that has only numbers... ... Read More

To check for Integer overflow, we need to check the Integer.MAX_VALUE with the subtracted integers result, Here, Integer.MAX_VALUE is the maximum value of an integer in Java.Let us see an example wherein integers are subtracted and if the result is more than Integer.MAX_VALUE, then an exception is thrown.The following is an example showing how to check for Integer overflow.Example Live Demopublic class Demo {    public static void main(String[] args) {       int val1 = 9898999;       int val2 = 8784556;       System.out.println("Value1: "+val1);       System.out.println("Value2: "+val2);       long sub = ... Read More

To check whether a character is in Uppercase or not in Java, use the Character.isUpperCase() method.We have a character to be checked.char val = 'K';Now let us use the Character.isUpperCase() method.if (Character.isUpperCase(val)) {    System.out.println("Character is in Uppercase!"); }else {    System.out.println("Character is in Lowercase!"); }Let us see the complete example now to check for Uppercase in Java.Example Live Demopublic class Demo {    public static void main(String []args) {       System.out.println("Checking for Uppercase character...");       char val = 'K';       System.out.println("Character: "+val);       if (Character.isUpperCase(val)) {          System.out.println("Character is ... Read More

To display printable characters, you need to work with the ASCII values from 32 to 127.With that, we are using the following, instead of System.out.println()System.out.write();The following displays all the printable characters.for (int i = 32; i < 127; i++) { System.out.write(i);Let us see the complete example.Example Live Demopublic class Demo {    public static void main(String []args) {       System.out.println("Printable characters...");       for (int i = 32; i < 127; i++) {          System.out.write(i);          if (i % 8 == 7)          System.out.write('');          else ... Read More

To assign int value to a char variable in Java would consider the ASCII value and display the associated character/ digit.Here, we have a char.char val;Now assign int value to it.val = 77;Now, when you will print the value of “val”, it would display the character associate with the value (ASCII) 77.The following is the complete example.Example Live Demopublic class Demo {    public static void main(String []args) {       char val;       val = 77;       System.out.print("Value: ");       System.out.println(val);    } }OutputValue: M

To reverse an integer in Java, try the following code −Example Live Demoimport java.lang.*; public class Demo {    public static void main(String[] args) {       int i = 239, rev = 0;       System.out.println("Original: " + i);       while(i != 0) {          int digit = i % 10;          rev = rev * 10 + digit;          i /= 10;       }       System.out.println("Reversed: " + rev);    } }OutputOriginal: 239 Reversed: 932In the above program, we have the following int value, which we will reverse.int i = 239;Now, loop through until the value is 0. Find the remainder and perform the following operations to get the reverse of the given integer 239.while(i != 0) {    int digit = i % 10;    rev = rev * 10 + digit;    i /= 10; }

To compare two Java short arrays, use the Arrays.equals() method.Let us first declare and initialize some int arrays.int[] arr1 = new int[] { 33, 66, 12, 56, 99 }; int[] arr2 = new int[] { 33, 66, 12, 56, 99 }; int[] arr3 = new int[] { 33, 66, 15, 56, 90 };Now let us compare any two of the above arrays.Arrays.equals(arr1, arr2));In the same way, work it for other arrays and compare themExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       int[] arr1 = new int[] { 33, 66, 12, 56, ... Read More

To pass an integer by reference in Java, try the following code −Example Live Demopublic class Demo {    public static void display(int[] arr) {       arr[0] = arr[0] + 50;;    }    public static void main(String[] args) {       int val = 50;       int[] myArr = { val };       display(myArr);       System.out.println(myArr[0]);    } }Output100In the above program, a custom method is created, which pass an int array.int val = 50; int[] myArr = { val }; display(myArr);In the method, we have performed mathematical operation on the value of array.public static void display(int[] arr) {    arr[0] = arr[0] + 50;; }The updated value is then displayed in the main.System.out.println(myArr[0]);