Here, you can find a lot of programming exercise and implementations in Java.
// Java
// IntelliJ IDEA
Doston Hamrakulov
Software Developer
Description:
There are two integer variables(or whatever type) and you should swap them in manually without using any build in function and any other variable.
public class First_exercise {
public static void main(String args[]){
int number_1 = 8;
int number_2 = 15;
number_1 = number_1 + number_2;
number_2 = number_1 - number_2;
number_1 = number_1 - number_2;
System.out.println("First: " + number_1);
System.out.println("Second: " + number_2);
}
}-[X] Exercise 2:
Description:
There is a String "Hello Doston Hamrakulov" and you need to reverse it. You have to show two ways of how to reverse the String by using build-in functions and doing manually.
public static void main(String args[]){
String var = "Hello Doston";
System.out.println(var);
System.out.println("\nUsing library:");
System.out.println(UsingLibrary(var));
System.out.println("\nDoing manually:");
System.out.println(Manually(var));
}
public static String UsingLibrary(String name){
String newName = new StringBuilder(name).reverse().toString();
return newName;
}
public static String Manually(String name){
char dos[] = new char[name.length()];
for (int i = 1; i <= name.length(); i++){
if (i > name.length()){
break;
} else {
dos[i-1] = name.charAt(name.length()-i);
}
}
return new String(dos) + "";
}Description:
Write a method in Java which takes String parameter and Character, then the method should remove the character from given String.
public static void main(String args[]){
String str = "Doston HaBBBBBv";
System.out.println("Third exercise:\n\n" + str);
System.out.println("Answer:\n\n" + MyMethod(str, 'B'));
}
private static String MyMethod(String str, char c){
if (str == null){
return null;
}
return str.replaceAll(Character.toString(c), "");
}Description:
Write a Java program which takes input of Integer number and outputs the ODD or EVEN of the entered number.
public static void main(String args[]){
int input;
Scanner sc = new Scanner(System.in);
System.out.println("Please, enter number");
input = sc.nextInt();
String num = "2019";
Integer a = Integer.valueOf(num);
int d = a.intValue();
if ((input % 2) == 0){
System.out.println("\nNumber is EVEN");
} else {
System.out.println("\nNumber is ODD");
}
}Description:
Write a Java program that reads an integer between 0 and 1000 and adds all the digits of that integer
public static void main(String args[]){
System.out.println(getSUM(2222));
}
static int getSUM(int num){
String a = String.valueOf(num);
int sum = 0;
for (int i = 0; i < a.length(); i++){
sum += Integer.parseInt(a.charAt(i) + "");
}
return sum;
}Description:
Write java program which find the lowest common multiple of two Integer number.
public static void main (String args[]){
System.out.println(MyMethod(8, 12));
}
public static int MyMethod(int x, int y)
{
int a;
a = (x > y) ? x : y; // a is greater number
while(true)
{
if(a % x == 0 && a % y == 0)
return a;
++a;
}
}Description:
Write program that outputs 10 times without using any loop ('for', 'while', 'do while', ect.)
static int index = 0;
static String temp = "";
public static void main(String[] args) {
System.out.println(printMore("1_", 10));
}
private static String printMore(String myStr, int i) {
temp += myStr;
index++;
if (index < i){
printMore(myStr, i);
}
return temp;
}-[ ] Exercise 8: Write a Java method to count all vowels in a string.