# Sieve of Eratosthenes - to find the prime numbers till n

Given a number N, calculate the prime numbers up to N using Sieve of Eratosthenes.

Example 1:

```
Input:
N = 10
Output:
2 3 5 7
Explanation:
Prime numbers less than equal to N
are 2 3 5 and 7.
```

Example 2:

```
Input:
N = 35
Output:
2 3 5 7 11 13 17 19 23 29 31
Explanation:
Prime numbers less than equal to 35 are
2 3 5 7 11 13 17 19 23 29 and 31.
```

code: c++ implementation

**void SieveOfEratosthenes(int n)
{
bool prime[n + 1];
memset(prime, true, sizeof(prime));
for (int p = 2; p * p <= n; p++)
{
if (prime[p] == true)
{
for (int i = p * p; i <= n; i += p)
prime[i] = false;
}
}
for (int p = 2; p <= n; p++)
if (prime[p])
cout << p << " ";
}**