update

src/12/c14/c14_prime.cpp

@@ -0,0 +1,49 @@
+#include <cstddef>
+#include <iostream>
+#include <ostream>
+#include <type_traits>
+#include <vector>
+
+using namespace std;
+
+template<class T>
+ostream&operator<<(ostream &os,vector<T> const& v){
+    os<<"{ ";
+    if(v.size()==0){
+        os<<" }";
+    }else{
+        for(size_t i=0;i<v.size()-1;i++){
+            os<<v[i]<<" ,";
+        }
+        os<<v[v.size()-1]<<" }";
+    }
+    return os;
+}
+
+vector<int> getPrimes(int const& end){
+    vector<bool> isFactor(end+1,false);
+    for(int i=2;i<end;i++){
+        if(isFactor[i]==false){
+            for(int j=i+i;j<end;j+=i){
+                isFactor[j]=true;
+            }
+        }
+    }
+    vector<int> primes;
+    for(int i=2;i<end;i++){
+        if(isFactor[i]==false){
+            // cout<<i<<' ';
+            primes.push_back(i);
+        }
+    }
+    return primes;
+}
+
+int main(){
+    // const auto primes =  getPrimeNum(101);
+    // for(int const& i:primes){
+    //     cout<<i<<' ';
+    // }
+    // cout<<'\n';
+    cout<<"primes nums: "<<getPrimes(100+1)<<'\n';
+}