Using c Create a program to find all the prime numbers betwe

Using c++

Create a program to find all the prime numbers between 1 and a enterted value . This time, use a classic
method called the \"Sieve of Eratosthenes.\"

Solution

#include <iostream>
using namespace std;

int main()
{
   int n=0;
   cout<<\"Please Enter the number upto to which you want to find the prime number:\";
   cin>>n;
int arr[n];
for(int i=0;i<n;i++){
   arr[i]=0; //intializing all the array elements to 0
   }
   for (int i=2;i<n;i++)
{
for (int j=i*i;j<n;j=i+j)   
{
arr[j-1] = 1; //setting non prime numbers to 1
}
}
for (int i=1;i<n;i++)
{
if (arr[i-1]==0) //the array elements whose value is 0 are prime numbers
cout<<i<<\" \"; //printing out the array index which are the prime numbers indeed.
}
}