Write a Program to Calculate grade points GPA in C++

PROGRAM:

#include<iostream>
using namespace std;
int main()
{
char grade; double gpa=0.0;
cout<<"Enter your Grade=  ";
cin>>grade;
switch(grade)
{
  case'A':
  case'a':
  gpa=4.0;
  cout<<"your GPA is "<<gpa;
  break;
  case'B':
  case'b':
  gpa=3.0;
  cout<<"your GPA is "<<gpa;
  break;
  case'C':
  case'c':
  gpa=2.0;
  cout<<"your GPA is "<<gpa;
  break;
  case'D':
  case'd':
  gpa=1.0;
  cout<<"your GPA is "<<gpa;
  break;
  case'F':
  case'f':
  gpa=0.0;
  cout<<"your GPA is "<<gpa;
  break;
  default:
  cout<<"invalid grade entered";
  break;
 }
return 0;
}