ClassQuiz2, C++ (gcc)

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//g++  7.4.0

/////////////////////////////////////////////////////////////////////////////
//ClassQuiz2
//quiz() code credit goes to thecleverprogrammer and SmallLion/Mr Unity Buddy of github
//rest of the code created by Rezaul Hoque on August 02,2022;
//contact:jewelmrh@yahoo.com;Dhaka,Bangladesh;https://rezaulhoque.wordpress.com,https://hoquestake.blogspot.com
//note: codes shared by Rezaul Hoque on rextester are not for sale; they are created and shared to facilitate the algorithm learning process; many like Hoque use this platform to practice programming ;Rezaul hopes his contribution helps others to fine tune their learning;
//////////////////////////////////////////////////////////////////////////////
#include <iostream>
#include <sstream>
#include <string>

//stream manipulator
std::ostream& l(std::ostream& os)
{
  return (os<<"\n");
}
namespace Pat{
void fill(char c)
{
std::cout.width(40);
std::cout.fill(c);
std::cout<<l;
}
}

namespace Quiz{
class Quiz{
public:
void welcome (){

std::stringstream s("Welcome to the quiz!You have 3 questions.Each right answer will bring you 10.");
std::cout<<s.str()<<l;
Pat::fill('~');
Pat::fill('~');
}

void quiz(){

std::string RightAns[]={"Everest","Amazon","Bering"};
int score=0;

std::string ans;
std::cout<<"What is the name of the highest peak of the world?\n";
std::stringstream o1("Alps,Mt. Everest,Kilimanjaro");
std::cout<<o1.str()<<l;
std::cin>>ans;
if (ans==RightAns[0])
 {
  std::cout<<" Right you are!\n";
 
  ++score;}
else
  {std::cout<<"That's not right\n";}

std::cout<<"Which one is the longest river on earth?\n";
std::stringstream o2("Ganges, Mississippi,Amazon");
std::cout<<o2.str()<<l;
std::cin>>ans;
if(ans==RightAns[1]){
  
  std::cout<<" Right you are!\n";
  
 ++score;
 }
else
  {std::cout<<"That's not right.\n";}

std::cout<<"Which strait lies between USA and Russia?\n";
std::stringstream o3("Palk,Hormuz,Bering");
std::cout<<o3.str()<<l;
std::cin>>ans;
if(ans==RightAns[2])
  {
  std::cout<<" Right you are!\n";
 ++score;}
else
  {std::cout<<"That's not right.\n";}

int m;
m=score*10;
std::cout<<"Your score is "<<m;
if(m<30)
  std::cout<<". Try better next time!\n";
else if(m==30)
 std::cout<<". Awesome!\n";
}
};
}

int main()
{
Pat::fill('@');
Pat::fill('@');
Quiz::Quiz q;
q.welcome();
q.quiz();

Pat::fill('@');
Pat::fill('@');
return 0;
  
}

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Compilation time: 0.92 sec, absolute running time: 0.16 sec, cpu time: 0.01 sec, memory peak: 5 Mb, absolute service time: 1,14 sec