Conditinal Statements

When setting up a series of conditional checks, it is best to structure them according to the logical relationships between the conditions you are checking for.

Why go through all this extra trouble?

• efficiency:
  • if done correctly, your conditionals should never have to check the same condition twice
• readability:
  • if done correctly, you will arrive at one of the simplest and most readable arrangements of conditional checks
• debugging and maintaining:
  • readable code is fixable code
  • when each condition is only checked in one place, it is easier to make sure you've corrected all bugs

The 3 relationships to consider:

1. Mutually Exclusive
   • the two conditions cannot be true at the same time: ie - are you dead? are you alive? have you ever existed?
2. Logical Dependancy
   • the two conditions are related. knowledge about one condition will effect your decision concerning the other condition: ie - did it rain? is the ground wet?
3. Locigally Independant
   • the two conditions are unrelated. knowledge of one condition provides no information on the other condition: ie - you woke up on time for class. i am dead.

Each classification calls for a differently structured conditional check:

1. Mutally Exclusive - 'if'/'else'/'else if' information:

if (it_is_a_ball) {
  roll_it;
} else if (it_is_a_cube) {
  stack_it;
} else {
  learn_more_shapes;
};

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2. Logically Dependant - nested if statements:

if (you_are_hungry) {
  if (you_can_cook) {
    make_food;
  } else {
    buy_food;
  };
} else {
  dont_eat;
};

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3. Logically Independant - sequential if statements

if (you_are_hungry) {
  if (you_can_cook) {
    make_food;
  } else {
    buy_food;
  };
} else {
  dont_eat;
};
if (it_is_a_ball) {
  roll_it;
} else if (it_is_a_cube) {
  stack_it;
} else {
  learn_more_shapes;
};

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Resources

counterpoint: https://revelry.co/coding-without-if-statements/

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