What does .compare do in c++? for example in this sorting function void employeeSort(string lastName[], char grades[], int n) { int i ; int j; for (i = 0; i 0) // If name at index j is greater than...

What does

.compare

do in c++?

for example in this sorting function

void
employeeSort(string lastName[],
char
grades[],
int
n)

{

int i;

    int
j;

for
(i = 0; i < n;="">

    {

for
(j = 0; j < n="" -="" i="" -="" 1;="">

        {

if
(lastName[j].compare(lastName[j + 1]) > 0) // If name at index j is greater than last name at index j + 1,
also this is where I need help, knowing what does .compare do and do to lastName[j].compare(lastName[j + 1]) > 0

            {

                string temp = lastName[j];

                lastName[j] = lastName[j + 1];

                lastName[j + 1] = temp; //Swaps names

char
tempo = grades[j];

                grades[j] = grades[j + 1];

                grades[j + 1] = tempo; //Swaps grades

            }

        }

    }

}