What is wrong with the following code fragment? $($See the tip back in $8.$ In that vein, it has NOTHING to do with the comment. The comment merely tells what else would have gone on between the variable declarations and the assignment statement.$)$

double growth$\_$rate;

long start$\_$popul, end$\_$popul;

$//$ fill in start and end $\_$popul with data

$//(...$probably using a cin$)$

growth$\_$rate $=$ end$\_$popul $/$ start$\_$popul;

In addition to finding and explaining the error, please tell me the name of the method used to fix this situation and show how it would be applied here.