# Program to print prime numbers in a given range using C++ STL

In this tutorial, we will be discussing a program to print prime numbers for a given range of numbers using the C++ Standard Template Library.

In this, we will be given two numbers say a and b. The task is to print all the coming prime numbers in this range. For this, we will be using the Sieve of Eratosthenes method by running it as a subroutine. Simultaneously we will be storing all the prime numbers in a vector and finally printing them all.

## Example

#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long int unll;
vector<unll> eratosthemes(unll n){
vector<bool> prime_num(n+1,true);
prime_num[0] = false;
prime_num[1] = false;
int m = sqrt(n);
for (unll p=2; p<=m; p++){
if (prime_num[p]){
for (unll i=p*2; i<=n; i += p)
prime_num[i] = false;
}
}
vector<unll< elements;
for (int i=0;i<n;i++)
if (prime_num[i])
elements.push_back(i);
return elements;
}
bool check_zero(unll i){
return i == 0;
}
vector<unll> sieve_range(unll start,unll end){
vector<unll> s1 = eratosthemes(start);
vector<unll> s2 = eratosthemes(end);
vector<unll> elements(end-start);
set_difference(s2.begin(), s2.end(), s1.begin(),
s2.end(), elements.begin());
vector<unll>::iterator itr =
remove_if(elements.begin(),elements.end(),check_zero);
elements.resize(itr-elements.begin());
return elements;
}
int main(void){
unll start = 10;
unll end = 90;
vector<unll> elements = sieve_range(start,end);
for (auto i:elements)
cout<<i<<' ';
return 0;
}

## Output

11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89

Updated on: 01-Nov-2019

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