A4 : prime number within N
find prime number within n;
#include <iostream> #include <vector> #include <set> #include <cmath> using namespace std; bool isPrime(int n) { if( n==2) return true; int temp = (int)sqrt( (double)n); for( int i=2; i<temp; i++) { if( n%i==0) return false; } return true; } vector<int> findPrime( int n ) { vector<bool> flags(n,true); vector<int> rel; for( int i=2; i<n; i++) { if( flags[i]){ if( isPrime(i) ) { rel.push_back( i ); int temp = i; int k = 2; while( temp<n) { flags[temp] = false; temp *= k; k++; } } } } return rel; } int main(int argc, char** argv) { vector<int> rel = findPrime( 1000); for(int i=0; i<rel.size(); i++) { cout<<rel[i]<<", "; } cout<<endl; }