Forked process goes in wrong path - c

Question

I have an assignment in C Language; the requirement is that I am given number of students, everyone has 2 grades midterm grade and final grade my task is to calculate the number of students who passed. But I will use forking; we will fork Teaching Assistants to separately choose whether a student should pass or not and the number of Teaching Assistants will be passed on terminal.
Everything is fine. I wrote the code, but I noticed something very weird, I got a segmentation fault which is so weird because I am sure I am not accessing wrong memory. I tried to print something (line 53) and I found that this line is printed 4 times actually, which is equal to number of children + parent, although this line above the fork(). My code creates more than one process (TA) and every TA takes a partition and calculate number of passed students and exit with this code and on parent I make for loop and wait until any child dies so I print its exit code.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
void main(int argc, char **argv)
{
int Number_of_TAs = atoi(argv[1]);
int leastgrade = atoi(argv[2]);
int size_of_array = 0;
int flag = 0;
int last_visited = 0;
int ind = 0;
FILE* ptr;
char ch;
// Opening file in reading mode
ptr = fopen("students.txt", "r");
if (NULL == ptr) {
printf("file can't be opened \n");
}
do {
ch = fgetc(ptr);
size_of_array = 2 * ((int)ch - 48);
break;
} while (ch != EOF);
fclose(ptr);
int arr_of_grades[size_of_array];
int arr_of_grades2[size_of_array/2];
FILE *myFile;
myFile = fopen("students.txt", "r");
int *dummy;
fscanf(myFile, "%d", &dummy);
for (int i = 0; i < size_of_array; i++)
fscanf(myFile, "%d", &arr_of_grades[i]);
int index2 = 0;
printf("%d", size_of_array);
printf(" ");
for (int i = 0; i< size_of_array; i=i+2)
{
arr_of_grades2[index2] = arr_of_grades[i] + arr_of_grades[i+1];
index2 = index2 + 1;
}
fclose(myFile);
int pid, stat_loc;
int passed_students = 0;
int partion = size_of_array / (2 * Number_of_TAs );
for (int i=0; i< Number_of_TAs; i++)
{
pid = fork();
ind = ind + partion;
}
if (pid == 0)
{
for (int i = ind; i< ind + partion; i++)
{
if (arr_of_grades2[i]>=leastgrade )
passed_students = passed_students + 1;
}
exit(passed_students);
}
else
{
int sid;
for (int i = 0; i<Number_of_TAs; i++)
{
sid = wait(&stat_loc);
if(!(stat_loc & 0x00FF))
printf(stat_loc>>8);
printf(" ");
}
}
return 0;
}
I am a newbie in C so I didn't try many things

Answer 1

The segmentation fault issue may happen at any array access with the wrong index.
In your case, it may happen at the first 2 lines:
int Number_of_TAs = atoi(argv[1]);
int leastgrade = atoi(argv[2]);
if you execute the program without the 2 parameters.
Another issue of your program is that you should move the if-else statement where you check the pid inside the for loop where you create the processes with the fork() otherwise it creates more processes than expected.