C++ grade system program

 #include <iostream>

using namespace std;

int main()

{

int m1,m2,m3,avg;

cout<<"enter the marks";

cin>>m1>>m2>>m3;

avg=(m1+m2+m3)/3;

if(avg>=75)

{cout<<"A+ with distinction";}

else if(avg>=60 && avg<75)

{cout<<"grade is A";}

else if(avg>=45 && avg<60)

{cout<<"grade is B";}

else if(avg>=40 && avg<45)

{cout<<"grade is C";}

else

{cout<<"grade is f";}

}