Programming and Problem Solving with Java

9.2 Additional Control Statements | 441

case'D' :
case'F' : outFile.print("Poor Work");
numberInTrouble++;
break; // Unnecessary, but a good habit
}

Note that the final breakstatement is unnecessary, but programmers often include it any-
way. One reason is that it’s easier to insert another case label at the end if a breakstatement
is already present.
If gradedoes not contain one of the specified characters, none of the statements within
the switchexecutes. It would be wise to add a defaultlabel to account for an invalid grade:

switch(grade)
{
case'A' :
case'B' : outFile.print("Good Work");
break;
case'C' : outFile.print("Average Work");
break;
case'D' :
case'F' : outFile.print("Poor Work");
numberInTrouble++;
break;
default : outFile.print(grade + " is not a valid letter grade.");
}

A switchstatement with a breakstatement after each case alternative behaves exactly
like an if-else-ifcontrol structure. For example, the preceding switchstatement is equivalent
to the following code:

if (grade == 'A' || grade == 'B')
outFile.print("Good Work");
else if(grade == 'C')
outFile.print("Average Work");
else if(grade == 'D' || grade == 'F')
{
outFile.print("Poor Work");
numberInTrouble++;
}
else
outFile.print(grade + "is not a valid letter grade.");

Is either of these two versions better than the other? There is no absolute answer to this
question. In this particular example, the switchstatement is easier to understand because