C++ sort() method with 1.default operator,2 stand library compare ,3custom function,4,lambda expression

#include <iostream>
#include <unistd.h>
#include <uuid/uuid.h>
#include <ctime>
#include <random>
#include <array>
#include <algorithm>
#include <functional>
#include <string_view>

using namespace std;

void sortArray1();
char* getTimeNow();

int main()
{
    sortArray1();
    return 0;
}

void sortArray1()
{
    srand(time(NULL));
    array<int,100> arr;
    int len=arr.size();
    for(int i=0;i<len;i++)
    {
        arr[i]=rand()%1000000;
    }

    auto print=[&arr](std::string_view const rem)
    {
        cout<<rem<<endl;
        for(auto num:arr)
        {
            cout<<num<<' ';
        } 
        cout<<endl<<endl;
    };

    print("Original array container elements");
     
    array<int,100>::iterator itr=arr.begin(); 
    sort(arr.begin(),arr.end()); 
    print("Sorted with the default operator<");
 
    sort(arr.begin(),arr.end(),std::greater<int>());
    print("Sorted with the standard library compare function object");

    struct 
    {
        bool operator()(int a,int b) const {return a<b;}
    } customLess;

    std::sort(arr.begin(),arr.end(),customLess);
    print("Sorted with a custom function object");

    std::sort(arr.begin(),arr.end(),[](int a,int b)
    {
        return a>b;
    });  
    print("Sorted with a lambda expression!");
    cout<<"\nFinished in random1() now is "<<getTimeNow()<<endl;
}

char* getTimeNow()
{
    time_t rawTime=time(NULL);
    struct tm tmInfo=*localtime(&rawTime);
    char *dtValue=(char*)malloc(40);
    strftime(dtValue,20,"%Y%m%d%H%M%S",&tmInfo);
    return dtValue;
}

Compile via below g++ command

g++ -g -std=c++2a -I. h1.cpp -o h1 -luuid

Run the compiled output

./h1

The finally effect illustrated as below.