c - While Loop doesn't stop executing

The "while" in my code doesn't stop running even when I type " ^Z "
it's supposed to stop since the EOF exists.
Any idea why?

 #define NUM_OF_GRADES 10
    int maxInArray();
    int main()
    {   char ch1;
        int grades[NUM_OF_GRADES];
        int grade;
        printf("Please enter a character:");
        printf("\n");
        scanf("%c",&ch1);
        printf("Please enter grades:");
        printf("\n");
        while (scanf("%d",&grade)!=EOF)
        {
           grades[grade-1]++;
        }
        return 0;
    }