File Redirection Input inC - c

Question

I'm creating a program that takes numbers from a separate .txt file and turns them into a factorial and then finds the amount of times each prime has occurred in the factorial.
I have been working on this code for the last few days and after many hours i keep getting stuck on the same thing, it will compile with no errors but when I try file redirection to get an input from another file it stops and acts like it is asking for input on an endless loop.
Any help would be much appreciated!
#include <stdio.h>
int Storage_array[5];
int current_prime, next_prime, factorial, prime_count, prime_number, num, factorial_current, factorial_next_num, current_number, total_number; //various variables used in program
int find_prime_count(int factorial, int prime_number); //3 functions declared below main()
int find_next_prime(int factorial, int current_prime);
int is_prime(int num);
int a, b, c; //utility varbles
main()
{
if((a=scanf("%d", &c)) == EOF) //checks to see if file is empty
{
return 0;
}
for(b=0; b<c; b++)
{
if((a=scanf("%d", &c)) == EOF) //checks to see if reached end of the file
{
break;
}
scanf("%d", &Storage_array[b]); //paces values from file into the storage array
printf("%d! = ", Storage_array[b]); //formatting the output
for(c=0;c<5;c++)
{
if(c=0) //creating a base case
{
current_prime = 2;
}
else
{
current_prime = next_prime; //updates the current prime after the base case
next_prime = find_next_prime(Storage_array[b], current_prime); //performes the outside functions that fine the next prime number within the factorial
prime_count = find_prime_count(Storage_array[b], current_prime); //performs outside function that finds the number of the current prime within the factorial
printf("(%d^%d)",current_prime ,next_prime); //prints the results in proper format
}
}
printf("\n"); //spaces between factorial numbers
}
}
int is_prime(int num) //function that determines if the input number is a prime number or not
{
for(a=2; a<num; a++) //base case knowing lowest prime is 2
{
if (num % a == 0) //determines if the number is a prime number using remainder when divided by various numbers
{
return a; //returns the number if it is prime
}
}
}
int find_prime_count (int factorial, int prime_number)
{
for(a=0;a<factorial;a++)//tests all possible prime numbers under the input factorial
{
if(a=0) //base case for lowest possible prime in factorial
{
factorial_current = 1;
factorial_next_num = 1;
}
else
{
factorial_current = (a*factorial_next_num);
}
if(factorial_current % prime_number == 0) //determines if the prime number fits into current factorial number
{
current_number = (factorial_current/prime_number); //finds number of times prime number fits in
total_number = (total_number + current_number); //adds total amount of times that prime has fit within the factorial
}
}
return total_number;
}
int find_next_prime (int factorial, int current_prime) //function that determines the next prime within the factorial
{
for(a=current_prime;a<factorial;a++) //checks all possible primes within the factorial
{
if (factorial % current_prime == 0) //determines if the number is a prime number using remainder when divided by various numbers
{
return a; //returns the number if it is next prime
}
}
}
the text file i have has the following content and is called input.txt
7
67
9
43
0