Needing help please....

Code:

   #include <stdio.h>
   #include <string.h>
   #include <stdlib.h>



   void readfile(char name, int grade1,int grade2,int grade3);
   int meangrade(int grade1,int grade2,int grade3);
   void display(char name, int grade1,int grade2,int grade3);
   int qsort(char name, int grade1, int grade2, int grade3, int meangrade);

     struct grades
    {
     char students[30];
     int grade1;
     int grade2;
     int grade3;
    };

      struct grades name[30], g1, g2, g3,*gptr;

      FILE *infile;
      FILE *outfile;

     int main(int argc, char **argv) {
    {
      char filename;
      int choice, exam;
     
      FILE *infile = fopen("grade.txt", "r");
      FILE *outfile = fopen("grades.txt","w");


      printf ("Please enter the filename needed:  \n");
      scanf("%c", &filename);
      printf("Please enter 1 for a specific exam to be displayed or 0 to exit. \n");
      scanf("%d", &choice);
         if (choice == 0)
             display;
         else
            printf("Goodbye....\n");

      fclose(infile);
      fclose(outfile);

      return 0;
   }
      void readfile(char filename,char name[30],int grade1,int grade2,int grade3){
      fscanf(infile,"%c %d%d%d", name[30], &grade1, &grade2,&grade3);
}
      int meangrade(int grade1,int grade2,int grade3,int meangrade){
      meangrade = (grade1 +grade2 +grade3)/3;
      return meangrade;
     }

      void display(char filename,char name[30], int grade1,int grade2,int grade3){
      int exam;
       printf("Which exam number would you like to see?    ");
       scanf("%d", &exam);
           if (exam > 3){
           printf("Please enter a valid exam number:  ");
           scanf("%d", &exam);
          }else
           fprintf(infile,"%s%d%d%d", name[30], &grade1,&grade2, &grade3);
         }


           int qsort(struct name[30], int grade1,int grade2,int grade3, int meangrade)
{
           int j, max;
           for(j = 0; j < 100; ++j) {
              if (name[j].grade1 > name[j].grade2)
                   max = name[j].grade1;
              else
                   max = name[j].grade2;
              if (name[j].grade3 > max)
                   max = name[j].grade3;
           return max;
        }
   }

I am getting these errors... I just don't understand... especially the sort issue.. Could someone please help.

Code:

grades.c:18: conflicting types for `qsort'
/local/gnu/lib/gcc-lib/sparc-sun-solaris2.8/3.0.4/include/iso/stdlib_iso.h:123: previous declaration of `qsort'
grades.c: In function `main':
grades.c:75: warning: `struct name' declared inside parameter list
grades.c:75: warning: its scope is only this definition or declaration, which is probably not what you want.
grades.c: In function `qsort':
grades.c:74: parameter name omitted
grades.c: In function `main':
grades.c:88: parse error at end of input

change your quicksort function name to quicksort, the function name qsort is already in use.

The parameter list of qsort in the declaration:

int qsort(char name,......

isn't the same as the parameter list in the definition

int qsort(struct name[30], ...

I suspect in the declaration you want

int qsort(char name[30],.....

and in the definition you want

int qsort(char name[30],.....

but then again.......