What if I don't write default in switch case?

Question

int a = 10;
switch(a){
case 0:
    printf(\"case 0\");
    break;
case 1:
    printf(\"case 1\");
    break;
}

Is the above code valid?

If

Answer 1

Default is not mandatory but always good to have it. The code is ideally but our life is not, no harm to put a protection there. It will also help you debugging if any unexpected thing happens.