End stands for the last element subscript of the matrix. Tru(end+ 1) dynamically expands the number of elements of tru.

End means the last element subscript of the matrix, for example:

& gt& gta=randn( 1，3)

a =

- 1.3077 -0.4336 0.3426

& gt& gt Answer (End)

ans =

0.3426

& gt& gta=randn(3，3)

a =

3.5784 3.0349 0.7 147

2.7694 0.7254 -0.2050

- 1.3499 -0.063 1 -0. 124 1

& gt& gt Answer (End)

ans =

-0. 124 1

Randn randomly generates a number.

ht=plot(tru，' g-')； Drawing design

Hang in there, keep the original picture and keep drawing.