Today, you will create a program to check if a number is prime. Prime numbers are an essential concept in mathematics and are often used in cryptography, algorithms, and data security.
A prime number is any number greater than 1 that is only divisible by 1 and itself. For example:
By solving this challenge, you will:
To determine if a number n is prime:
# Get input from the user
number = int(input("Enter a number: "))
# Check if the number is prime
if number <= 1:
print(f"{number} is not a prime number.")
else:
is_prime = True
for i in range(2, number): # Check divisors from 2 to number-1
if number % i == 0:
is_prime = False
break
if is_prime:
print(f"{number} is a prime number.")
else:
print(f"{number} is not a prime number.")
import math
# Get input from the user
number = int(input("Enter a number: "))
# Check if the number is prime
if number <= 1:
print(f"{number} is not a prime number.")
else:
is_prime = True
for i in range(2, int(math.sqrt(number)) + 1): # Only check up to the square root of the number
if number % i == 0:
is_prime = False
break
if is_prime:
print(f"{number} is a prime number.")
else:
print(f"{number} is not a prime number.")
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
// Get input from the user
System.out.print("Enter a number: ");
int number = scanner.nextInt();
if (number <= 1) {
System.out.println(number + " is not a prime number.");
} else {
boolean isPrime = true;
for (int i = 2; i < number; i++) { // Check divisors from 2 to number-1
if (number % i == 0) {
isPrime = false;
break;
}
}
if (isPrime) {
System.out.println(number + " is a prime number.");
} else {
System.out.println(number + " is not a prime number.");
}
}
}
}
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
// Get input from the user
System.out.print("Enter a number: ");
int number = scanner.nextInt();
if (number <= 1) {
System.out.println(number + " is not a prime number.");
} else {
boolean isPrime = true;
for (int i = 2; i <= Math.sqrt(number); i++) { // Only check up to the square root
if (number % i == 0) {
isPrime = false;
break;
}
}
if (isPrime) {
System.out.println(number + " is a prime number.");
} else {
System.out.println(number + " is not a prime number.");
}
}
}
}
// Get input from the user
let number = parseInt(prompt("Enter a number:"));
if (number <= 1) {
console.log(`${number} is not a prime number.`);
} else {
let isPrime = true;
for (let i = 2; i < number; i++) { // Check divisors from 2 to number-1
if (number % i === 0) {
isPrime = false;
break;
}
}
if (isPrime) {
console.log(`${number} is a prime number.`);
} else {
console.log(`${number} is not a prime number.`);
}
}
// Get input from the user
let number = parseInt(prompt("Enter a number:"));
if (number <= 1) {
console.log(`${number} is not a prime number.`);
} else {
let isPrime = true;
for (let i = 2; i <= Math.sqrt(number); i++) { // Only check up to the square root
if (number % i === 0) {
isPrime = false;
break;
}
}
if (isPrime) {
console.log(`${number} is a prime number.`);
} else {
console.log(`${number} is not a prime number.`);
}
}
This task builds a solid foundation for working with numbers and understanding algorithms in programming!
Get ready for Day 11: Sum of Numbers, where you’ll create a program that calculates the sum of all numbers from 1 to a user-provided number n.