also I used isInteger boolean condition to check that lowInteger and highInteger is an integer that return an error
an if statement to check that lowInteger and highInteger returns error if they are less than zoro
then if lowInteger is greater than highInteger then assign lowInteger to a temperary holder variable
then assign value of lowInteger to highInteger
then return the value of temperary holder back to highInteger
create a variable that holds the final sumAll
loop through the lowInteger and assign the final value to finalSum then return finalSum