//C program to calculate GPA
#include<stdio.h>
#include<conio.h>

main()

{

 char a[8];float b;int i;int n[8];char c;
 start:
 clrscr();

 printf("\nCopyright(c)2012 Winston\n\n\nEnter the Grades in this Order.\neg:cdeacaed\nCY2111     Chemistry");

 printf("\nGE2111     EG      ");

 printf("\nGE2112     FOCP     ");

 printf("\nGE2115     CP    ");

 printf("\nGE2116     EP       ");

 printf("\nHS2111     English ");

 printf("\nMA2111     Maths  ");

 printf("\nPH2111     Physics  ");

 printf("\nEnter Grades:");
 scanf("%s",a);

 for(i=0;i<8;i++)                        /*Checking each character*/

  {

   if(a[i]=='s') n[i]=10;

   if(a[i]=='a') n[i]=9;

   if(a[i]=='b') n[i]=8;

   if(a[i]=='c') n[i]=7;

   if(a[i]=='d') n[i]=6;

   if(a[i]=='e') n[i]=5;

  }
  //The grades points are multiplied by credits and summed up
  b=n[0]*3+n[1]*5+n[2]*3+n[3]*2+n[4]*2+n[5]*4+n[6]*4+n[7]*3;

  printf("GPA %0.2f",b/26);        /*Dividing by total number of credits,%0.2f for two decimal points */
  printf("\nPress c to continue or any key to exit");
  c=getche();
  if(c=='c') goto start;
  getch();

}

I did this during the time of my first semester results
Very useful for bulk calculation of GPA.
Download the source code and the executable here.GPA-calculator