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package language;
public class ControlFlow {
public static void main(String[] argList) {
Fact.factorial(6);
}
}
class Fact {
static int factorial(int i) {
if (i < 0) {
throw new IllegalArgumentException("negative: " + i);
}
if (i > 100) {
throw new IllegalArgumentException("big: " + i);
}
return (i == 0 ? 1 : i * factorial(i-1));
}
}
/**
* Demonstrate recursive calls.
* @author Erik Hilsdale
*/
aspect LogFactorial {
// START-SAMPLE language-cflowRecursionBasic Pick out latest and original recursive call
/** call to factorial, with argument */
pointcut f(int i) : call(int Fact.factorial(int)) && args(i);
/** print most-recent recursive call */
before(int i, final int j) : f(i) && cflowbelow(f(j)) {
System.err.println(i + "-" + j);
}
/** print initial/topmost recursive call */
before(int i, final int j) : f(i)
&& cflowbelow(cflow(f(j)) && !cflowbelow(f(int))) {
System.err.println(i + "@" + j);
}
// END-SAMPLE language-cflowRecursionBasic
}
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