AgeGroupHisto, C++ (gcc)

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//g++  7.4.0
////////////////////////////////////////////////////////////////////////////////AgeGroupHisto: example of system generated current time and printing histogram
//this code is created by Rezaul Hoque on June 01,2022;
//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 <string>
#include <ctime>
#include <map>
#include <iomanip>
#include <random>

int main()
{
time_t t;
t=time(0);
std::cout<<"Date:\n";
std::cout<<ctime(&t);
std::cout<<"___________________________\n";
    std::random_device rd;
std::map<int,int> a{{1,10},{2,10},{3,20},{3,25},{4,30},{5,60}};
std::cout<<"Age group Respondents:\n";
std::cout<<"___________________________\n";
std::cout<<"      Responsents     Histo\n";
std::cout<<"____________________________\n";
for(auto p: a){
std::cout<<std::fixed<<std::setprecision(1)<<p.first/2.0*10<<"-"<<(p.first+1)/2.0*10;
std::cout<<"    "<<p.second<<"  |"<<std::string(p.second/10,'+')<<"\n";}
return 0;
}

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Compilation time: 4.13 sec, absolute running time: 0.16 sec, cpu time: 0 sec, memory peak: 6 Mb, absolute service time: 4,38 sec