Average of marks of subjects using C++ programming language

Program:

#include<iostream>
using namespace std;
int main()
{
double n,sum=0;
double avg;
int j;
cout<<"enter number of subjects you have : ";
cin>>n;
for(int i=1;i<=n;i++)
{
cout<<"enter marks for "<<i<<" subject : ";
cin>>j;
sum=sum+j;
}
cout<<"the sum of all subject marks is: "<<sum;
avg=sum/n;
cout<<"\nthe average of all subjects is : "<<avg;
return 0;
}

output:

enter number of subjects you have : 5

enter marks for 1 subject : 45

enter marks for 2 subject : 44

enter marks for 3 subject : 43

enter marks for 4 subject : 43

enter marks for 5 subject : 34

the sum of all subject marks is: 209

the average of all subjects is : 41.8