Hello!

As part of the Challenage proposed for the 'Getting Started with Apex' trailhead topic, I am tryting the following:
Create an Apex class that returns an array (or list) of formatted strings ('Test 0', 'Test 1', ...). The length of the array is determined by an integer parameter. 
The Apex class must be called 'StringArrayTest' and be in the public scope.
The Apex class must have a public static method called 'generateStringArray'.
The 'generateStringArray' method must return an array (or list) of strings. Each string must have a value in the format 'Test n' where n is the index of the current string in the array. The number of returned strings is specified by the integer parameter to the 'generateStringArray' method.

If I create a class just with the first 3 lines of the following code and execute the rest in an anonymous windows, it works as expected. However, could I have everything just in one class?

public class StringArrayTest {
    public static Integer generateStringArray = 10;
}
        for(Integer i=0;i<StringArrayTest.generateStringArray;i++) {
            System.debug('Test '+ i);
        }

Many thanks!
Jesus

Sales Managers have asked for an at-a-glance solution to see completeness on leads. Create a helper formula field that looks at 5 key fields on the Lead object and evaluates their completeness, then a second formula field that references the helper formula and returns an image.

>The helper formula field should be on the Lead object with a name of 'Lead Quality Helper' and a resulting API name of 'Lead_Quality_Helper__c'.
>The helper formula should be of type Number.
>The helper formula should evaluate the following 5 fields: Email, Phone, Company, Title, and Industry and return 0 if blank and 1 if not blank. >The formula should then add all the values together to return a total value.
>The image formula should be on the Lead object with a name of 'Lead Quality' and a resulting API name of 'Lead_Quality__c'.
>The image formula should reference the helper formula, and return an image based on the number returned by the helper formula. The helper formula should be of type Text. Note: All of these images are already available in your Developer Edition.

1 = /img/samples/stars_100.gif with alternate text '1 star'
2 = /img/samples/stars_200.gif with alternate text '2 stars'
3 = /img/samples/stars_300.gif with alternate text '3 stars'
4 = /img/samples/stars_400.gif with alternate text '4 stars'
5 = /img/samples/stars_500.gif with alternate text '5 stars'

If none of the fields are filled out, the default should be /img/samples/stars_000.gif with alternate text '0 stars'.
The 'Lead Quality' formula must be added to the Lead Layout page layout.

ok so im having trouble on this challenege on trailhead. im confused what it means by helper formula, like how would we create a helper formular? also how would we create a image formula?

thanks if anyone answers