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Selecting from Many Options with Switch Statements

Selecting from Many Options with Switch Statements

If you have many options to choose from, use a switch statement. A switch statement tests a value and can have many case statements which define various possible values. Statements are executed from the first matched case value until a break is encountered.

Here is a pseudocode example:

  switch(num) {
    case value1:
      statement1;
      break;
    case value2:
      statement2;
      break;
    ...
    case valueN:
      statementN;
      break;
  }

A bit more explanation

A switch statement first evaluates its expression. It then looks for the first case clause whose expression evaluates to the same value as the result of the input expression (using the strict comparison, (===) and transfers control to that clause, executing the associated statements. (If multiple cases match the provided value, the first case that matches is selected, even if the cases are not equal to each other.)

If no matching case clause is found, the program looks for the optional default clause, and if found, transfers control to that clause, executing the associated statements. If no default clause is found, the program continues execution at the statement following the end of switch. By convention, the default clause is the last clause, but it does not need to be so.

The optional break statement associated with each case label ensures that the program breaks out of switch once the matched statement is executed and continues execution at the statement following switch. If break is omitted, the program continues execution at the next statement in the switch statement.¹

Problem Explanation:

Write a switch statement which tests val and sets answer for the following conditions:

1 - "alpha",
2 - "beta",
3 - "gamma",
4 - "delta".

Hint 1

Remember that case values are tested with strict equality (===).

Try to solve the problem now!

Hint 2

Do not see "following conditions" as an ordered list as it looks in the original freeCodeCamp demo, but as values and statements, as shown here

Try to solve the problem now!

Spoiler Alert!

Are you completely sure what you want a look? ...

Basic Code Solution

function caseInSwitch(val) {
  var answer = "";
  // Only change code below this line
  switch(val) {
    case 1:
      return "alpha";
      break;
    case 2:
      return "beta";
      break;
    case 3:
      return "gamma";
      break;
    case 4:
      return "delta";
      break;
  }

  // Only change code above this line  
  return answer;  
}

// Change this value to test
caseInSwitch(1);

Code Explanation

It is common to ignore that case values are tested with strict equality with any need of other expression, like so: case === value

Alternative code solution:

function caseInSwitch(val) {
  var answer = "";
  // Only change code below this line
  switch (val){
    case 1:
      answer="alpha";
      break;
    case 2:
      answer="beta";
      break;
    case 3:
      answer="gamma";
      break;
    case 4:
      answer="delta";
      break;
  }
  // Only change code above this line  
  return answer;  
}
// Change this value to test
caseInSwitch(1);

· Run code at repl.it.

Code explanation

Since you already have a variable defined at the beginning of the function named answer and it's defined as the last return statement, you can assign new values to it for each case and will return the expected answer depending on the value you pass to the function.

Sources

1. Description of "switch" - MDN JavaScript reference.

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