How to plot points from a geometric transformation matrix?

In the following code I need to change the plot function code every time the number of vertices change. Is there a function which can plot any number of vertices?

clc
clear
n=input('Enter the number of vertices')
for i=1:n
    x(i)=input('Enter the x coordinate');
    y(i)=input('Enter the y coordinate');
end
a=[x;y;ones(1,n)]
ro=[-1 0 0;0 -1 0;0 0 1];
disp('The final Matrix is')
c=ro*a
grid on
hold on
X1=[a(1,1),a(1,2),a(1,3),a(1,4),a(1,1)];
Y1=[a(2,1),a(2,2),a(2,3),a(2,4),a(2,1)];
plot(X1,Y1,'g')
fill(X1,Y1,'g')
X2=[c(1,1),c(1,2),c(1,3),c(1,4),c(1,1)];
Y2=[c(2,1),c(2,2),c(2,3),c(2,4),c(2,1)];
plot(X2,Y2,'r')
fill(X2,Y2,'r')
hold off

Answer 1

[KSSV]

clc
clear
n=input('Enter the number of vertices')
for i=1:n
    x(i)=input('Enter the x coordinate');
    y(i)=input('Enter the y coordinate');
end
a=[x;y;ones(1,n)]
ro=[-1 0 0;0 -1 0;0 0 1];
disp('The final Matrix is')
c=ro*a
grid on
hold on
X1=[a(1,:) a(1,1)] ; 
Y1=[a(2,:) a(2,1)] ; 

plot(X1,Y1,'g')
fill(X1,Y1,'g')

X2=[c(1,:) c(1,1)] ; 
Y2=[a(2,:) a(2,1)] ;

plot(X2,Y2,'r')
fill(X2,Y2,'r')
hold off

[Rohit Raut]

Thank you so much!