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An alternative to nested if-else statements is C++'s switch
statement.
If different courses of action are to be taken for different integer values,
a switch statement is appropriate. Here is a comparison
of switch and Racket's cond statement:
(define movie-rating
(lambda (rating)
(cond ((= rating 4)
(display "Excellent"))
((= rating 3)
(display "Good"))
((= rating 2)
(display "Fair"))
((= rating 1)
(display "Crappy"))
(else
(display "Invalid rating")))))
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void movieRating(int rating) {
switch (rating) {
case 4: {
cout << "Excellent";
break;
}
case 3: {
cout << "Good";
break;
}
case 2: {
cout << "Fair";
break;
}
case 1: {
cout << "Crappy";
break;
}
default:
cout << "Invalid rating";
}
}
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- The expression after the switch keyword (rating in the
example) must give an integer (or "scalar") value
- Control then passes to the case clause corresponding to the
integer value, whose code is executed
- If the code for the matching case clause does not include
a break statement, the code for the succeeding case clause is
also executed
- If the integer value does not match any case clause, the code for
the default clause is executed
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