This line declares the function lengthOfLastWord that takes a string s as input and returns an integer.

This line initializes a variable len to 0, which will be used to keep track of the length of the last word.

This line initializes a variable i to the index of the last character in the string s.

This line starts a while loop that checks if i is greater than or equal to 0 and if the character at index i of the string s is a space. If both conditions are true, the loop decrements i by 1 until it finds a non-space character.

This line starts another while loop that checks if i is greater than or equal to 0 and if the character at index i of the string s is not a space. If both conditions are true, the loop increments len by 1 and decrements i by 1 until it reaches the beginning of the last word.

This line returns the value of len, which is the length of the last word in the string.