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Instructor requests inappropriate switch statement application>?

jjmounes (20)
Okay so he wants me to rewrite this code:

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int score;
cout << "Enter your score: ";
cin >> score;

if(score >= 60 && score < 70) 
cout << "D" << endl;
else if(score >= 70 && score < 80)
cout << "C" << endl;
else if(score >= 80 && score < 90)
cout << "B" << endl;
else if(score >= 90)
cout << "A" << endl;
else 
cout << "U" << endl;

system("pause");

return 0;


(simple enough)

"Replace the if-else if-...-else with switch. This step has a little challenge!

Okay, now that's great and all, but I can't figure out how to design a switch statement to accept a range of values- they don't seem to be for that at all dammit but I have to do what he asks. What's killing me is he says replace. I could just make each range output 1, 2, 3, 4, 5. Then tack a switch statement on. But then, I wouldn't have replaced the if...else, only added to it needlessly.

This class is dumb, sigh.
jjmounes (20)
For clarity, this is the same thing using a completely unnecessary and backwards switch statement to handle the output.

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if(score >= 60 && score < 70) 
grade = 'D';
else if(score >= 70 && score < 80)
grade = 'C';
else if(score >= 80 && score < 90)
grade = 'B';
else if(score >= 90)
grade = 'A';
else 
grade = 'U';

switch(grade)
{
case 'A':
		cout << "You got an A.\n";
		break;
case 'B':
		cout << "You got a B.\n";
		break;
case 'C':
		cout << "You got a C.\n";
		break;
case 'D':
		cout << "You got a D.\n";
		break;
case 'U':
		cout << "You didn't pass.\n";
		break;
}


I'm about to write a program that replaces the if...else structure with a switch statement

All 100 bloody cases. Argh.
Maese909 (131)
To accomplish what your professor is asking you to do, I highly recommend doing the following:
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switch(score / 10)
{
case 0:
case 1:
.
.
.
case 10:
}


I am sure you can figure out what needs to be done from there.
Last edited on
shacktar (1187)
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switch(score)
{
    case –2147483648:
    case –2147483647:
    case –2147483646:
    //...
    case 0:
    case 1:
    case 2:
    //...
    case 58:
    case 59:
        cout << "U" << endl;
        break;

    case 60:
    case 61:
    //...
    case 69:
        cout << "D" << endl;
        break;

    case 70:
    case 71:
    //...
    case 79:
        cout << "C" << endl;
        break;

    case 80:
    case 81:
    //...
    case 89:
        cout << "B" << endl;
        break;

    default:
        cout << "A" << endl;
        break;
}


You'll want to write a program to generate all the cases for the else branch. Hopefully your instructor will realize they're in error.
Last edited on
jjmounes (20)
Thank you Maese, that was a real "aha" moment. Surely this is what he was hoping for.

Shacktar, that's what I was thinking I would do just do be a dick.

Much obliged.
hanst99 (2869)
Well, gcc provides an extension for using ranges in switches. Then again, as you have already said yourself that's not what switches are for (well, I personally think that in 99% of all cases in which switches are used it's due to laziness of the programmer rather than an actual need anyways).
jjmounes (20)
Switches seem useful for building menus since they have a limited scope by definition. Other than that, I dunno.
hanst99 (2869)
For menus, use polymorphy. Unless it's really simple test code or just some stupid homework you have to hand in.
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