Grade point average (GPA) is a measure of a student's academic achievement at an educational institution. A student's GPA is calculated by dividing the total number of grade quality points they earn by the total number they attempt. The result, rounded off to two decimal places, is the student's GPA.

This GPA calculator will prompt the user to enter a student's grades.  After each grade is entered by the user, the program will give the use the option to continue entering grades or to stop entering grades and calculate the GPA.

Code:

#include <iostream>

using namespace std;
int main(int argc, char *argv[])
{

	const double A = 4.0;
    const double A_MINUS = 3.67;
	const double B_PLUS = 3.33;
	const double B = 3.0;
	const double B_MINUS = 2.67;
	const double C_PLUS = 2.33;
	const double C = 2.0;
	const double C_MINUS = 1.67;
	const double D = 1.00;
	const double F = 0.0;
	
	string lettergrade;
 	double credit;
    double caltimes = 0;
    double totalcal = 0;
    double totalcredit = 0;
    double finalgpa = 0;
    int option;
  
 	for(;;)
    {           
        cout<<"\nEnter letter grade: ";
        cin>>lettergrade;
        cin.ignore();
        cout<<"Enter the course credit: ";
        cin>>credit;
    
			   
		if(lettergrade == "a" || lettergrade == "A")
		{
			caltimes = credit * A;
		}
		else if(lettergrade == "a-" || lettergrade == "A-")
		{
			caltimes = credit * A_MINUS;
		}
		else if(lettergrade == "b+" || lettergrade == "B+")
		{
			caltimes = credit * B_PLUS;
		}
		else if(lettergrade == "b" || lettergrade == "B")
		{
			caltimes = credit * B;
		}
		else if(lettergrade == "b-" || lettergrade == "B-")
		{
			caltimes = credit * B_MINUS;
		}
		else if(lettergrade == "c+" || lettergrade == "C+")
		{
			caltimes = credit * C_PLUS;
		}
		else if(lettergrade == "c" || lettergrade == "C")
		{
			caltimes = credit * C;
		}
		else if(lettergrade == "c-" || lettergrade == "C-")
		{
			caltimes = credit * C_MINUS;
		}
		else if(lettergrade == "d" || lettergrade == "D")
		{
			caltimes = credit * D;
		}
		else if(lettergrade == "f" || lettergrade == "F")
		{
			caltimes = credit * F;
		}	   
		else
		{
			cout<<"Invaild Input...";
		}
	
	             
          totalcredit = totalcredit + credit;
          totalcal = totalcal + caltimes;
          
		  cout<<"Do you want to enter another grade (1 - Yes, 2 - no): ";
		  cin>>option;
		  if(option == 1)
		  {
		  	continue;
		  }
		  else
		  {
		  	break;
		  }      
 	}
                
          finalgpa = totalcal/totalcredit;
          cout<<"Student's GPA: "<<finalgpa<<"\n";
    
	
	return 0;
}