DAY 1

1) 

for (numberOfIncompletes=0,k=0; k<incompletes.length; k++) {
    if (incompletes[k] == studentID) {
        numberOfIncompletes++;
    }
}

2) 

Enter any number: 3
3 spring
Enter any number: 6
6 summer
Enter any number: 9
9 fall
Enter any number: 12
12 winter
Enter any number: 0
0 error
Enter any number: 15
15 error
Enter any number: 2
2 winter
Enter any number: 5
5 spring
Enter any number: 8
8 summer