int main()
{
  int asgn1, asgn2, asgn3, asgn4, test1, test2, exam, a1good, a2good, a3good, a4good, t1good, t2good, egood, asum, tsum, esum, fasgn;
  float weight1, weight2, weight3, allscore, score, i, fsum, n;
  char grade;
   
     
  //asks to enter in all the grades of the student (meaning input)

  
  
  printf("Please enter four assignment grades, two test grades, and one exam grade for each student:\n"); 
  printf("Enter first assignment grade: ");
  scanf("%d", &asgn1);
  printf("Enter second assignment grade: ");
  scanf("%d", &asgn2);
  printf("Enter third assignment grade: ");
  scanf("%d", &asgn3);
  printf("Enter fourth assignment grade: ");
  scanf("%d", &asgn4);
  printf("Enter first test grade: ");
  scanf("%d", &test1);
  printf("Enter second test grade: ");
  scanf("%d", &test2);
  printf("Enter exam grade: ");
  scanf("%d", &exam);
  //now to make sure grades are within the appropriate range will will declare parameters from 0 to 100.
  a1good=asgn1>=0&&asgn1<=100;
  a2good=asgn2>=0&&asgn2<=100;
  a3good=asgn3>=0&&asgn3<=100;
  a4good=asgn4>=0&&asgn4<=100;
  t1good=test1>=0&&test1<=100;
  t2good=test2>=0&&test2<=100;
  egood=exam>=0&&exam<=100;
  allscore=a1good, a2good, a3good, a4good, t1good, t2good, egood;
    if(allscore)
    {
       printf("all scores are good for calculation\n");
    }
    else 
    {
       printf("one or more scores are bad, please re-enter the scores\n");
       system("pause");
       return 0;
    }
  //now we must calculate the needed scores and percentages
  asum = asgn1 + asgn2 + asgn3 + asgn4; // assignment sum
  weight1 = (asum/4)*.2; // assignment weighed at 20%
  printf("Your weighted assignment grade is=%f\n", weight1);
  tsum = test1 + test2; // test sum
  weight2 = (tsum/2)*.3; // test weighed at 30%
  printf("Your weighted test grade is=%f\n", weight2);
  weight3 = exam*.5; // exam weighed at 50%
  printf("Your weighted exam grade is=%f\n", weight3);
  score = weight1 + weight2 + weight3;
    if(score<=100 && score>=85) // if statements will 
    {
      grade = 'A';
    }
    else if(score>=74)
    {
      grade = 'B';
    }
    else if(score>=63)
    {
      grade = 'C';
    }
    else if(score>=52)
    {
      grade = 'D';
    }
    else if(score<52)
    {
      grade = 'F';
    }
    else if(score<0)
    {
      grade = 'N';
    }
  printf("grade=%c\n", grade);
  system("pause");
  return 0;
}

/* system("pause");  
use: */
getchar(); /* instead.    Why???  because , it's the C way and NOT the M$ way.*/ 

allscore=a1good, a2good, a3good, a4good, t1good, t2good, egood;

 int class_grades[max_nstudents][ngrades];

#include <stdio.h>

int main(void)
{
  #define NGRADES 3
  int a1good, a2good, a3good, allgood, good, i;
  int asgn[NGRADES];
  double gradetot= 0;

  /** point 1 **/
  a1good= 0;
  a2good= a3good = 1;
  allgood= a1good, a2good, a3good;
  printf("\nallgood= %d \n\
  So you can see, allgood only gets value of first item\n", allgood );

  /** point 2 use arrays and loops for input **/
  printf("\nInstead of trying to manage asgn1, asgn2, asgn3, use an array \n");
  for(i= 0; i < NGRADES; i++ )
  {
    good = 0;
    while(!good)
    {
      printf("  Enter assignment grade %d: ", i);
      scanf("%d", &asgn[i]);

      /* qualify the input here if it's out of arange get it again  */
      if( asgn[i] < 0 || asgn[i] > 100)
      {
        printf("Input out of range, try again. \n");
      }
      else
      {
        good++;
      }
    }
  }

  /** point 2.1  use arrays and loops for analysis and output **/
  printf("\nThe scores you entered were: ");
  for( i= 0; i < NGRADES; i++)
  {
    printf(" %d", asgn[i] );
    gradetot += asgn[i] ;      /* do other things like add the grades up */
  }
  printf(".  The grade average is: total:%d / %d = %.2f \n",
                         (int)gradetot, NGRADES, (gradetot / NGRADES) );

  /** point 3 don't use system("pause"); it is the mark of the beast **/
  printf("\nsystem(\"pause\"); <-- only works for microsoft not linux \n");
  printf("Use a standard C blocking function like getchar(); instead like this <hit enter>\n");

  /** BUT WAIT, since you used scanf above we need a 
      point 3.1  scanf() will always leave at least '\n' in stdin 
      so before you try to use getchar we need to read out all   **/

  { int c;  while( (c= getchar()) != '\n' && c != EOF );  }

  /* note that the braces create a new 'scope' in which we can declare c */
  /* now we can use getchar(); */
  printf("OK , now <hit enter>: ");
  getchar();

  return 0;
}