Using character in string to find a print data lines

Question

So i have an array of strucures, lets say student grades. A undetermined lenght list of data (loaded by a file) in the format student:test1:test2:lettergrade I want to be able to "search" by prompting the user to enter a letter grade, and after hitting enter, the program finds all student lines with that letter grade and prints them out.

After doing some research i've thought maybe doing a strrchr would be the solution. but besides coming to that conclusion i'm sort of at a loss... Can anybody point me in the right direction here?

here is what i've attempted to try so far... when i try to run this, after i enter the letter grade to search, my program crashes.

void gradeLetter (STUREC records[], int count)
{

int j;
char letter;
int s;
int i;

printf("Enter letter grade you wish to view: ");
scanf("%s", letter);

for(j = 0; j < count; j++)
    {s = strrchr (records[count].grade, "letter");

  if (s != NULL)
  {

    printf("\n+---------------------------+--------+--------+--------+--------+--------+--------+---------+-------+\n");
    printf("| Student Name              |   ID   | Test 1 | Test 2 | Proj 1 | Proj 2 | Proj 3 | Average | Grade |\n");
    printf("+---------------------------+--------+--------+--------+--------+--------+--------+---------+-------+\n");

    for (i = 0; i < count; i++)
    {
        int count = printf( "| %s, %s", records[i].lname, records[i].fname );
if ( count < NAME_LEN )
    printf( "%*s", NAME_LEN - count, "" ); printf ("| %-7.6d| %4d   | %4d   | %4d   | %4d   | %4d   | %6.2f  |  %-2s   |\n", records[i].id, records[i].score1,
                 records[i].score2, records[i].score3, records[i].score4, records[i].score5,
                  records[i].ave, records[i].grade);
    }
    printf("+---------------------------+--------+--------+--------+--------+--------+--------+---------+-------+\n");

    }
    }

  return 0;
}