int numbers[] = {2, 3, 5, 7, 11, 13, 17};
size_t count = sizeof numbers / sizeof numbers[0];
for (size_t i = 0; i < count; i++) {
printf("numbers[%zu] is %d\n", i, numbers[i]);
}
//printed:
//numbers[0] is 2
//numbers[1] is 3
//numbers[2] is 5
//numbers[3] is 7
//numbers[4] is 11
//numbers[5] is 13
//numbers[6] is 17