Simple Java programs for beginners
Rani Singh
Some Simple Java programs that are great for beginners:
1. Hello World Program:
public class HelloWorld
{
public static void main(String[] args)
{
System.out.println("Hello, world!");
}
}
2. Sum of Two Numbers:
public class SumTwoNumbers
{
public static void main(String[] args)
{
int num1 = 5, num2 = 10, sum;
sum = num1 + num2;
System.out.println("Sum of " + num1 + " and " + num2 + " is: " + sum);
}
}
3. Fibonacci Series:
public class FibonacciSeries
{
public static void main(String[] args)
{
int n1 = 0, n2 = 1, n3, count = 10;
System.out.print(n1 + " " + n2);
for (int i = 2; i < count; i++)
{
n3 = n1 + n2;
System.out.print(" " + n3);
n1 = n2;
n2 = n3;
}
}
}
4. Reverse a String:
public class ReverseString
{
public static void main(String[] args)
{
String str = "Hello, world!";
String reverse = "";
for (int i = str.length() - 1; i >= 0; i--)
{
reverse += str.charAt(i);
}
System.out.println("Original string: " + str);
System.out.println("Reversed string: " + reverse);
}
}
5. Factorial of a Number:
public class Factorial
{
public static void main(String[] args)
{
int num = 5, fact = 1;
for (int i = 1; i <= num; i++) {
fact = fact * i;
}
System.out.println("Factorial of " + num + " is: " + fact);
}
}
6. Simple Calculator:
import java.util.Scanner;
public class Calculator
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("Enter two numbers: ");
double num1 = input.nextDouble();
double num2 = input.nextDouble();
System.out.println("Enter an operator (+, -, *, /): ");
char operator = input.next().charAt(0);
double result;
switch(operator)
{
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
result = num1 / num2;
break;
default:
System.out.println("Invalid operator");
return;
}
System.out.println(num1 + " " + operator + " " + num2 + " = " + result);
}
}
7. Guess the Number Game:
import java.util.Scanner;
public class GuessNumber
{
public static void main(String[] args)
{
int randomNumber = (int) (Math.random() * 100) + 1;
Scanner input = new Scanner(System.in);
int guess;
int count = 1;
do {
System.out.println("Guess a number between 1 and 100: ");
guess = input.nextInt();
if (guess > randomNumber)
{
System.out.println("Too high. Try again.");
count++;
} else if (guess < randomNumber) {
System.out.println("Too low. Try again.");
count++;
} else
{
System.out.println("Congratulations! You guessed the number in " + count + " tries.");
}
} while (guess != randomNumber);
}
}
8. Print Multiplication Table:
import java.util.Scanner;
public class MultiplicationTable
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("Enter a number: ");
int num = input.nextInt();
for (int i = 1; i <= 10; i++) {
System.out.println(num + " x " + i + " = " + (num * i));
}
}
}
9. Fahrenheit to Celsius Conversion:
import java.util.Scanner;
public class FahrenheitToCelsius
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("Enter temperature in Fahrenheit: ");
double fahrenheit = input.nextDouble();
double celsius = (fahrenheit - 32) * 5 / 9;
System.out.println(fahrenheit + "F = " + celsius + "C");
}
}
