CPP program to use maps

Source Code:
#include<iostream>
#include<map>
using namespace std;
int main()
{
map<string,int> grades;
grades["Suva"]=78;
grades["Soumyo"]=83;
grades["Nitai"]=92;
string name;
cout<<"Enter a name to find: ";
cin>>name;
if(grades.find(name)!=grades.end())
{
cout<<name<<": "<<grades[name]<<endl;
}
else
{
cout<<name<<" "<<"not found."<<endl;
}
double average=0.0;
int sum=0;
map<string,int>::iterator it=grades.begin();
while(it!=grades.end())
{
sum+=it->second;
++it;
}
cout<<endl;
average=sum/grades.size();
cout<<"The average grade is: "<<average<<endl;
return 0;
}

Program Output :