Para un número dado N, el propósito es encontrar todos los números primos del 1 al N.
Ejemplos:
Java
// Java program to find all the
// prime numbers from 1 to N
class gfg {
// Function to print all the
// prime numbers till N
static void prime_N(int N)
{
// Declaring the variables
int x, y, flg;
// Printing display message
System.out.println(
"All the Prime numbers within 1 and " + N
+ " are:");
// Using for loop for traversing all
// the numbers from 1 to N
for (x = 1; x <= N; x++) {
// Omit 0 and 1 as they are
// neither prime nor composite
if (x == 1 || x == 0)
continue;
// Using flag variable to check
// if x is prime or not
flg = 1;
for (y = 2; y <= x / 2; ++y) {
if (x % y == 0) {
flg = 0;
break;
}
}
// If flag is 1 then x is prime but
// if flag is 0 then x is not prime
if (flg == 1)
System.out.print(x + " ");
}
}
// The Driver code
public static void main(String[] args)
{
int N = 45;
prime_N(N);
}
}
Java
// Java program to find all the
// prime numbers from 1 to N
class gfg {
// Function to print all the
// prime numbers till N
static void prime_N(int N)
{
// Declaring the variables
int x, y, flg;
// Printing display message
System.out.println(
"All the Prime numbers within 1 and " + N
+ " are:");
// Using for loop for traversing all
// the numbers from 1 to N
for (x = 2; x <= N; x++) {
// Using flag variable to check
// if x is prime or not
flg = 1;
for (y = 2; y * y <= x; y++) {
if (x % y == 0) {
flg = 0;
break;
}
}
// If flag is 1 then x is prime but
// if flag is 0 then x is not prime
if (flg == 1)
System.out.print(x + " ");
}
}
// The Driver code
public static void main(String[] args)
{
int N = 45;
prime_N(N);
}
}
Java
// Java program to print all
// primes smaller than or equal to
// n using Sieve of Eratosthenes
class SieveOfEratosthenes {
void sieveOfEratosthenes(int n)
{
// Create a boolean array
// "prime[0..n]" and
// initialize all entries
// it as true. A value in
// prime[i] will finally be
// false if i is Not a
// prime, else true.
boolean prime[] = new boolean[n + 1];
for (int i = 0; i <= n; i++)
prime[i] = true;
for (int p = 2; p * p <= n; p++) {
// If prime[p] is not changed, then it is a
// prime
if (prime[p] == true) {
// Update all multiples of p
for (int i = p * p; i <= n; i += p)
prime[i] = false;
}
}
// Print all prime numbers
for (int i = 2; i <= n; i++) {
if (prime[i] == true)
System.out.print(i + " ");
}
}
// Driver Code
public static void main(String args[])
{
int N = 45;
System.out.println(
"All the Prime numbers within 1 and " + N
+ " are:");
SieveOfEratosthenes g = new SieveOfEratosthenes();
g.sieveOfEratosthenes(N);
}
}
Publicación traducida automáticamente
Artículo escrito por Kanchan_Ray y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA