perchè questo programma mi genera un errorre sul sistema operativo(segnalazione di errori)

#include<stdio.h>


int main()
{
int counter;
int grade;
int total;
int average;

total = 0;
counter = 1;

while ( counter <=10){
printf ("enter grade");
scanf("%d,&grade");
total = total + grade;
counter = counter + 1;
}
average = total / 10;
printf ("Class average is %d\n",average);

return 0;
}