Dados dos números a y b como rango de intervalo, la tarea es encontrar los números primos entre este intervalo.
Ejemplos:
Input : a = 1, b = 10 Output : 2, 3, 5, 7 Input : a = 10, b = 20 Output : 11, 13, 17, 19
En el siguiente programa, el rango de números se toma como entrada y se almacena en las variables ‘a’ y ‘b’. Luego, usando for-loop, se recorren los números entre el intervalo de a y b. Para cada número en el bucle for, se comprueba si este número es primo o no. Si encuentra primo, imprima el número. Luego se verifica el siguiente número en el bucle, hasta que se verifiquen todos los números.
Programa:
C++
// C++ program to find the prime numbers
// between a given interval
#include <bits/stdc++.h>
using namespace std;
int main()
{
// Declare the variables
int a, b, i, j, flag;
// Ask user to enter lower value of interval
cout << "Enter lower bound of the interval: ";
cin >> a; // Take input
// Ask user to enter upper value of interval
cout << "\nEnter upper bound of the interval: ";
cin >> b; // Take input
// Print display message
cout << "\nPrime numbers between "
<< a << " and " << b << " are: ";
// Traverse each number in the interval
// with the help of for loop
for (i = a; i <= b; i++) {
// Skip 0 and 1 as they are
// neither prime nor composite
if (i == 1 || i == 0)
continue;
// flag variable to tell
// if i is prime or not
flag = 1;
for (j = 2; j <= i / 2; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
cout << i << " ";
}
return 0;
}
// This code is contributed by Akanksha Rai
C
// C program to find the prime numbers
// between a given interval
#include <stdio.h>
int main()
{
// Declare the variables
int a, b, i, j, flag;
// Ask user to enter lower value of interval
printf("Enter lower bound of the interval: ");
scanf("%d", &a); // Take input
// Ask user to enter upper value of interval
printf("\nEnter upper bound of the interval: ");
scanf("%d", &b); // Take input
// Print display message
printf("\nPrime numbers between %d and %d are: ", a, b);
// Traverse each number in the interval
// with the help of for loop
for (i = a; i <= b; i++) {
// Skip 0 and 1 as they are
// neither prime nor composite
if (i == 1 || i == 0)
continue;
// flag variable to tell
// if i is prime or not
flag = 1;
for (j = 2; j <= i / 2; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
printf("%d ", i);
}
return 0;
}
Java
import java.util.Scanner;
// Java program to find the prime numbers
// between a given interval
public class GFG {
// driver code
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
// Declare the variables
int a, b, i, j, flag;
// Ask user to enter lower value of interval
System.out.printf("Enter lower bound of the interval: ");
a = sc.nextInt(); // Take input
// Ask user to enter upper value of interval
System.out.printf("\nEnter upper bound of the interval: ");
b = sc.nextInt(); // Take input
// Print display message
System.out.printf("\nPrime numbers between %d and %d are: ", a, b);
// Traverse each number in the interval
// with the help of for loop
for (i = a; i <= b; i++) {
// Skip 0 and 1 as they are
// neither prime nor composite
if (i == 1 || i == 0)
continue;
// flag variable to tell
// if i is prime or not
flag = 1;
for (j = 2; j <= i / 2; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
System.out.println(i);
}
}
}
Python3
# Python3 program to find the prime
# numbers between a given interval
if __name__ == '__main__':
# Declare the variables
a, b, i, j, flag = 0, 0, 0, 0, 0
# Ask user to enter lower value of interval
print("Enter lower bound of the interval:",
end = "")
a = int(input()) # Take input
print(a)
# Ask user to enter upper value of interval
print("Enter upper bound of the interval:",
end = "")
b = int(input()) # Take input
print(b)
# Print display message
print("Prime numbers between", a, "and",
b, "are:", end = "")
# Traverse each number in the interval
# with the help of for loop
for i in range(a, b + 1):
# Skip 1 as1 is neither
# prime nor composite
if (i == 1):
continue
# flag variable to tell
# if i is prime or not
flag = 1
for j in range(2, i // 2 + 1):
if (i % j == 0):
flag = 0
break
# flag = 1 means i is prime
# and flag = 0 means i is not prime
if (flag == 1):
print(i, end = " ")
# This code is contributed
# by Mohit kumar 29
C#
// C# program to find the prime numbers
// between a given interval
using System;
class GFG{
// Driver code
public static void Main(string[] args)
{
// Declare the variables
int a, b, i, j, flag;
// Ask user to enter lower value of interval
Console.WriteLine("Enter lower bound of " +
"the interval: ");
// Take input
a = int.Parse(Console.ReadLine());
// Ask user to enter upper value of interval
Console.WriteLine("\nEnter upper bound " +
"of the interval: ");
// Take input
b = int.Parse(Console.ReadLine());
// Print display message
Console.WriteLine("\nPrime numbers between " +
"{0} and {1} are: ", a, b);
// Traverse each number in the interval
// with the help of for loop
for(i = a; i <= b; i++)
{
// Skip 0 and 1 as they are
// neither prime nor composite
if (i == 1 || i == 0)
continue;
// flag variable to tell
// if i is prime or not
flag = 1;
for(j = 2; j <= i / 2; ++j)
{
if (i % j == 0)
{
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
Console.WriteLine(i);
}
}
}
// This code is contributed by jana_sayantan
Javascript
<script>
// JavaScript program to find the prime numbers
// between a given interval
// driver code
// Declare the variables
let a, b, i, j, flag;
// Ask user to enter lower value of interval and take input
a = window.prompt("Enter lower bound of the interval: ");
// Ask user to enter upper value of interval and take input
b = window.prompt("Enter upper bound of the interval: ");
// Print display message
console.log("Prime numbers between " + a + " and " + b << " are: ");
// Traverse each number in the interval
// with the help of for loop
for (i = a; i <= b; i++) {
// Skip 0 and 1 as they are
// neither prime nor composite
if (i == 1 || i == 0)
continue;
// flag variable to tell
// if i is prime or not
flag = 1;
for (j = 2; j <= i / 2; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
document.write(i," ");
}
// This code is contributed by shinjanpatra
</script>
Producción:
Enter lower bound of the interval: 1 Enter upper bound of the interval: 10 Prime numbers between 1 and 10 are: 2 3 5 7
Solución optimizada:
la idea es utilizar el hecho de que los números pares (excepto el 2) no son primos.
C++
// C++ program to find the prime numbers
// between a given interval
#include <bits/stdc++.h>
using namespace std;
int main()
{
// Declare the variables
int a, b, i, j;
// Ask user to enter lower value of interval please not
// interval < 0 cannot be prime numbers
cout << "Enter lower bound of the interval: ";
cin >> a; // Take input
// Ask user to enter upper value of interval
cout << "\nEnter upper bound of the interval: ";
cin >> b; // Take input
// Print display message
cout << "\nPrime numbers between " << a << " and " << b
<< " are: ";
// Explicitly handling the cases when a is less than 2
// since 0 and 1 are not prime numbers
if (a <= 2) {
a = 2;
if (b >= 2) {
cout << a << " ";
a++;
}
}
// MAKING SURE THAT a IS ODD BEFORE WE BEGIN
// THE LOOP
if (a % 2 == 0)
a++;
// NOTE : WE TRAVERSE THROUGH ODD NUMBERS ONLY
for (i = a; i <= b; i = i + 2) {
// flag variable to tell
// if i is prime or not
bool flag = 1;
// WE TRAVERSE TILL SQUARE ROOT OF j only.
// (LARGEST POSSIBLE VALUE OF A PRIME FACTOR)
for (j = 2; j * j <= i; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1){
if(i==1)
continue;
else
cout << i << " ";
}
}
return 0;
}
Java
import java.util.*;
public class PrimeNumbersInRange {
// function which checks whether a number is Prime or Not
// If the number is prime, it returns true. Else, it returns false.
public static boolean isPrime(int n) {
// 0 and 1 are neither prime nor composite numbers
if (n == 0 || n == 1) {
return false;
}
// 2 is a prime number
if (n == 2) {
return true;
}
// every composite number has a prime factor
// less than or equal to its square root.
for (int i = 2; i * i <= n; i++) {
if (n % i == 0) {
return false;
}
}
return true;
}
// Driver code
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
// Ask user to enter lower value of interval
System.out.print("Enter lower bound of the interval: ");
int lower = sc.nextInt(); // Take input
// Ask user to enter upper value of interval
System.out.print("\nEnter upper bound of the interval: ");
int upper = sc.nextInt(); // Take input
// Print display message
System.out.printf("\nPrime numbers between %d and %d are: ", lower, upper);
for (int i = lower; i <= upper; i++) {
if (isPrime(i)) {
System.out.print(i + " ");
}
}
sc.close();
}
}
Python3
# Python3 program to find the prime
# numbers between a given interval
if __name__ == '__main__':
# Declare the variables
a, b, i, j = 0, 0, 0, 0
# Ask user to enter lower value of interval
print("Enter lower bound of the interval:",end = "")
a = int(input()) # Take input
print(a)
# Ask user to enter upper value of interval
print("Enter upper bound of the interval:",end = "")
b = int(input()) # Take input
print(b)
# Print display message
print("Prime numbers between", a, "and",b, "are:", end = "")
# Explicitly handling the cases when a is less than 2
if (a == 1):
print(a,end=" ")
a+=1
if (b >= 2):
print(a,end=" ")
a+=1
if (a == 2):
print(a,end=" ")
# MAKING SURE THAT a IS ODD BEFORE WE BEGIN
# THE LOOP
if (a % 2 == 0):
a+=1
# NOTE : WE TRAVERSE THROUGH ODD NUMBERS ONLY
for i in range(a,b+1,2):
# flag variable to tell
# if i is prime or not
flag = 1
# WE TRAVERSE TILL SQUARE ROOT OF j only.
# (LARGEST POSSIBLE VALUE OF A PRIME FACTOR)
j = 2
while(j * j <= i):
if (i % j == 0):
flag = 0
break
j+=1
# flag = 1 means i is prime
# and flag = 0 means i is not prime
if (flag == 1):
print(i,end=" ")
# This code is contributed by shubhamsingh10
C#
// C# program to find the prime numbers
// between a given interval
using System;
class GFG
{
// Driver code
static public void Main()
{
// Declare the variables
int a, b, i, j, flag;
// Ask user to enter lower value of interval
Console.Write(
"Enter lower bound of the interval: ");
a = Convert.ToInt32(
Console.ReadLine()); // Take input
// Ask user to enter upper value of interval
Console.Write(
"\nEnter upper bound of the interval: ");
b = Convert.ToInt32(
Console.ReadLine()); // Take input
// Print display message
Console.Write("\nPrime numbers between " + a
+ " and " + b + " are: ");
// Explicitly handling the cases when a is less than
// 2
if (a == 1)
{
Console.Write(a + " ");
a++;
if (b >= 2)
{
Console.Write(a + " ");
a++;
}
}
if (a == 2)
{
Console.Write(a + " ");
}
// MAKING SURE THAT a IS ODD BEFORE WE BEGIN
// THE LOOP
if (a % 2 == 0)
{
a++;
}
// NOTE : WE TRAVERSE THROUGH ODD NUMBERS ONLY
for (i = a; i <= b; i = i + 2)
{
// flag variable to tell
// if i is prime or not
flag = 1;
// WE TRAVERSE TILL SQUARE ROOT OF j only.
// (LARGEST POSSIBLE VALUE OF A PRIME FACTOR)
for (j = 2; j * j <= i; ++j)
{
if (i % j == 0)
{
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1)
{
Console.Write(i + " ");
}
}
}
}
// This code is contributed by rag2127
Javascript
<script>
// JavaScript program to find the prime numbers
// between a given interval
// driver code
// Declare the variables
let a, b, i, j;
// Ask user to enter lower value of interval and take input
a = window.prompt("Enter lower bound of the interval: ");
// Ask user to enter upper value of interval and take input
b = window.prompt("Enter upper bound of the interval: ");
// Print display message
console.log("Prime numbers between " + a + " and " + b << " are: ");
// Explicitly handling the cases when a is less than 2
// since 0 and 1 are not prime numbers
if (a <= 2)
{
a = 2;
if (b >= 2)
{
document.write(a," ");
a++;
}
}
// MAKING SURE THAT a IS ODD BEFORE WE BEGIN
// THE LOOP
if (a % 2 == 0)
a++;
// NOTE : WE TRAVERSE THROUGH ODD NUMBERS ONLY
for (i = a; i <= b; i = i + 2) {
// flag variable to tell
// if i is prime or not
let flag = 1;
// WE TRAVERSE TILL SQUARE ROOT OF j only.
// (LARGEST POSSIBLE VALUE OF A PRIME FACTOR)
for (j = 2; j * j <= i; ++j) {
if (i % j == 0) {
flag = 0;
break;
}
}
// flag = 1 means i is prime
// and flag = 0 means i is not prime
if (flag == 1){
if(i == 1) continue;
else
document.write(i, " ");
}
}
// This code is contributed by shinjanpatra
</script>
Producción:
Enter lower bound of the interval: 1 Enter upper bound of the interval: 10 Prime numbers between 1 and 10 are: 2 3 5 7
Publicación traducida automáticamente
Artículo escrito por RishabhPrabhu y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA