Crazy "solution" to lightsaber question, grabbing the testcase answer off the stack...

[darrellroot]

Here's a standard solution for "How many lightsabers do you own?" in C https://www.codewars.com/kata/51f9d93b4095e0a7200001b8

int HowManyLightsabersDoYouOwn(char *name){
  if(strncmp(name, "Zach", 10) == 0){ 
    return 18;
  } else { 
    return 0;
  }
}

But one of my students was confused and "solved" it with this (I edited the printf slightly), which passed all the tests!

int HowManyLightsabersDoYouOwn(const char *name, int howMany) {
  printf("%d\n", howMany);
  return("%d\n", howMany);
}

First, note how he added an extra parameter to the function. Here's what the test case looks like:

Test(lightsabers_count, sample_tests) {
    // Zach has 18 Lightsabers
    do_test("Zach", 18);
    // Adam has 0 
    do_test("Adam", 0);
    // Alice has 0
    do_test("Alice", 0);
}

And here's the log output from the test cases (with my modified printf):

Log
18
0
0

I think what's happening is the extra parameter is taking the next integer off of the stack, which happens to be the next parameter to the testcase!

Not helpful for learning C, but completely crazy and I thought I'd share.