Counting_Sort_Date

#include <bits/stdc++.h>
using namespace std;
struct date
{
    long d;   //id
    long m;  //string s
    long y;     //mark
};
void counting_sort_date(long n,date arr[],date brr[])
{
    /**************************/
    long k=arr[0].d;
    for(long i=0;i<n;i++)
        if(k<arr[i].d)
            k=arr[i].d;
    /***************************/   //k=100;

    long crr[k+20];
    for(long i=0;i<=k;i++)
    {
        crr[i]=0;
    }

    for(long i=0;i<n;i++)
    {
        crr[arr[i].d]=crr[arr[i].d]+1;            //replace d with mark
    }
    for(long j=1;j<=k;j++)
    {
        crr[j]=crr[j]+crr[j-1];
    }
    //cout<<k;
    for(long j=n-1;j>=0;j--)
    {
        brr[crr[arr[j].d]-1]=arr[j];
        crr[arr[j].d]=crr[arr[j].d]-1;
    }
    //cout<<k;
}
void counting_sort_month(long n,date arr[],date brr[])
{
    long k=arr[0].m;
    for(long i=0;i<n;i++)
        if(k<arr[i].m)
            k=arr[i].m;


    long crr[k+20];
    for(long i=0;i<=k;i++)
    {
        crr[i]=0;
    }

    for(long i=0;i<n;i++)
    {
        crr[arr[i].m]=crr[arr[i].m]+1;
    }
    for(long j=1;j<=k;j++)
    {
        crr[j]=crr[j]+crr[j-1];
    }
    //cout<<k;
    for(long j=n-1;j>=0;j--)
    {
        brr[crr[arr[j].m]-1]=arr[j];
        crr[arr[j].m]=crr[arr[j].m]-1;
    }
    //cout<<k;
}

void counting_sort_year(long n,date arr[],date brr[])
{
    long k=arr[0].y;
    for(long i=0;i<n;i++)
        if(k<arr[i].y)
            k=arr[i].y;


    long crr[k+20];
    for(long i=0;i<=k;i++)
    {
        crr[i]=0;
    }

    for(long i=0;i<n;i++)
    {
        crr[arr[i].y]=crr[arr[i].y]+1;
    }
    for(long j=1;j<=k;j++)
    {
        crr[j]=crr[j]+crr[j-1];
    }
    //cout<<k;
    for(long j=n-1;j>=0;j--)
    {
        brr[crr[arr[j].y]-1]=arr[j];
        crr[arr[j].y]=crr[arr[j].y]-1;
    }
    //cout<<k;
}
int main()
{

    long n;
    cout<<"Enter number of date: "<<endl;
    cin>>n;
    date arr[n],drr[n],mrr[n],yrr[n];
    cout<<"Enter "<<n<<" dates in DD MM YYYY format: "<<endl;
    for(long i=0;i<n;i++)
    {
        cin>>arr[i].d;
        cin>>arr[i].m;
        cin>>arr[i].y;
    }
    counting_sort_date(n,arr,drr);  //counting_sort_mark(structure size, name, result structure);
    counting_sort_month(n,drr,mrr);
    counting_sort_year(n,mrr,yrr);
    cout<<"Output of "<<n<<" dates in DD MM YYYY format: "<<endl;
    for(long i=0;i<n;i++)        //reverse print i=n-1;i>=0;i--
    {
        cout<<yrr[i].d<<" ";       //result structure[index].id,  .name,     .mark
        cout<<yrr[i].m<<" ";
        cout<<yrr[i].y<<" "<<endl;
    }
}