Function Description:

The empty function returns $1$ if Vector is empty and $0$ if it is not empty.

The push function inserts the value at the end of the vector. At this time, for the allocation size of the vector, it is changed according to the number of elements as described.

The pop function deletes the last element of the vector and returns the value. At this time, the assignment size of the vector is changed according to the number of elements as described above. If the vector is empty, return $-1.$

The front function returns the earliest element of the vector $($an element with index $1).$ If the vector is empty, it returns $-1.$

The back function returns the last element of the vector. If the vector is empty, it returns $-1.$

The print all function outputs all elements of the vector. At this time, the $0$th index of the vector means the number of vector elements, not elements, so it is excluded. If the vector is empty, it returns $-1.$