Print prime numbers in a given range using C++ STL

It is the program to print prime numbers in a given range.

Algorithms

Begin    Declare a user define datatype stl.    Declare a vector number to the stl datatype.    Declare variable a to the stl datatype.    Declare vector Prime_Number to the Boolean datatype.       Prime_Number[0] = false.       Prime_Number[1] = false.    Declare b to the integer datatype.       Initialize b = sqrt(a).    for (stl pr=2; pr<=b; pr++)       if (Prime_Number[pr]) then          for (stl i=pr*2; i<=a; i += pr)             Prime_Number[i] = false.    Declare result to the vector type.    for (int i=0;i<a;i++)       if (Prime_Number[i]) then          result.push_back(i).       return result. End Begin    Declare function remove_zero() to the Boolean type.    Declare i to the stl datatype.    Return i = 0. End Begin    Declare a vector Number_Range to the stl datatype.    Declare First_Num, Last_Num to the stl datatype.    Pass them as parameter.    Declare two vector s1 and s2 to the stl datatype.       Initialize s1 = number(First_Num) to find primes from o to First_Num.       Initialize s2 = number(Last_Num) to find primes from o to Last_Num.    Declare vector result(Last_Num-First_Num) to the stl datatype.    Call set_difference(s2.begin(), s2.end(), s1.begin(), s2.end(), result.begin()) to find set difference of two vectors.    Declare an iterator itr to the vector type.       Initialize itr = remove_if(result.begin(),result.end(),remove_zero) to remove extra zeros.    Call resize (itr-result.begin()) to resize the result.    Return result.    Declare First_Num, Last_Num to the stl datatype.       Initialize First_Num = 20, Last_Num = 50.    Declare a vector result to the stl datatype.       Initialize result = Number_Range(First_Num,Last_Num).    Print "The Prime Numbers from 20 to 50 are: “    for (auto i:result)       Print the values of i. End.

Example

 Live Demo

#include<bits/stdc++.h> using namespace std; typedef unsigned long long int stl; vector<stl> number(stl a) {    vector<bool> Prime_Number(a+1,true);    Prime_Number[0] = false;    Prime_Number[1] = false;    int b = sqrt(a);    for (stl pr=2; pr<=b; pr++) {       if (Prime_Number[pr]) {          for (stl i=pr*2; i<=a; i += pr)             Prime_Number[i] = false;       }    }    vector<stl> result;    for (int i=0;i<a;i++)       if (Prime_Number[i])          result.push_back(i);    return result; } bool remove_zero(stl i) {     // Used to remove zeros from a vector    return i == 0; } vector<stl> Number_Range(stl First_Num,stl Last_Num) {    vector<stl> s1 = number(First_Num); // find primes from o to First_Num    vector<stl> s2 = number(Last_Num); // find primes from o to Last_Num    vector<stl> result(Last_Num-First_Num);    set_difference(s2.begin(), s2.end(), s1.begin(), s2.end(), result.begin()); // find set //difference of two vectors    vector<stl>::iterator itr = remove_if(result.begin(),result.end(),remove_zero); //remove extra zeros.    result.resize(itr-result.begin());    return result; } int main(void) {    stl First_Num = 20, Last_Num = 50;    vector<stl> result = Number_Range(First_Num,Last_Num);    cout<<"The Prime Numbers from "<<First_Num<<" to "<<Last_Num<< " are: ";    for (auto i:result)       cout<<i<<' ';    return 0; }

Output

The Prime Numbers from 20 to 50 are: 23 29 31 37 41 43 47