merge sort c++ implementation

#include<iostream>
using namespace std;
class sorting
{
int a[10],n;
public:
sorting()
{
cout<<"Number of Element:-";
cin>>n;
cout<<"Unsorted Element:-";
for(int i=1;i<=n;i++)
{
cin>>a[i];
}
int p=1;
int r=n;
merge(p,r);
}
void operation(int p,int q,int r)
{
int n1=-p+1+q;
int n2=r-q;
int L[10];
int R[10];
L[n1+1]=9999;
R[n2+1]=9999;
for(int i=1;i<=n1;i++)
{
L[i]=a[p+i-1];
}
for(int i=1;i<=n1;i++)
{
R[i]=a[q+i];
}
int i=1;
int j=1;
for(int k=p;k<=r;k++)
{
if(L[i]<R[j])
{
a[k]=L[i];
i++;
}
else
{
a[k]=R[j];
j++;
}
}
}
void merge(int p,int r)
{
if(p<r)
{
int q=(p+r)/2;
merge(p,q);
merge(q+1,r);
operation(p,q,r);
}
}
void disp()
{
cout<<"Sorted Element:-";
for(int i=1;i<=n;i++)
{
cout<<a[i]<<endl;
}
}
};
int main()
{
sorting x;
x.disp();
}