5 Conditional Statements and Loops

 

After reading this lesson, you’ll be able to:

  • Control the execution of your code using an if-else statement.
  • Iterate through instructions using while and for loops

In lesson 4, you have learned how to define values and variables to store some computation results. But life is not always so linear: when performing a task, you may also need to make informed decisions by selecting one approach rather than the other. In this lesson, you’ll discover how to combine different executions of your code through given conditions. You’ll learn how to use the most common conditional statements and loops in Scala. You’ll use if-else statements to check if the system should allow a requested operation in the capstone.

Consider this

In the previous lesson, you have written a program to mark exams from one to ten. Suppose you need to label a mark as follows: “Badly Failed” if the score is lower than four, “Failed” if between four and six excluded, “Passed” if between six and nine excluded, “Passed with Honors” otherwise. How would you implement this new functionality?

5.1   If-else statement

Suppose you have a list of events: each one has a number representing the day of the week it occurs, starting with one for Sunday and ending with seven for Saturday. You want to write a function that takes an integer representing a day of the week and returns either “weekday” or “weekend” accordingly. For example, you could come up with a solution similar to the following:

5.2   While Loop

5.3   For Loop

5.4   Summary

5.5   Answers to quick checks