matlab绘制散点图问题

Question

例如，要绘制一个二维坐标图的散点图，要求：
1、画出点A(2,3) B(4,5) C(6,7) D(1,6)这几个点，并用黑色点表示
2、画出X(4,3)这个点，并用红色点表示
3、将X点与ABCD四个点分别用红色直线相连
请问怎么编写，谢谢！

Answer 1

axis([0 8 0 8])

hold on

plot(2,3,'k*',4,5,'k*',6,7,'k*',1,6,'k*',4,3,'ro')

text(1.6,3,'A','FontSize',12),text(4.2,5,'B','FontSize',12)

text(6.2,7,'C','FontSize',12),text(1.2,6,'D','FontSize',12)

text(4.2,3,'X','FontSize',12)

line([2 4],[3 3],[0 0],'Color','r','LineWidth',3,'LineStyle','-')

line([4 4],[5 3],[0 0],'Color','r','LineWidth',3,'LineStyle','-')

line([6 4],[7 3],[0 0],'Color','r','LineWidth',3,'LineStyle','-')

line([1 4],[6 3],[0 0],'Color','r','LineWidth',3,'LineStyle','-')

Answer 2

a=[2 ,4 ,6,1,4;3,5,7,6,3];
plot(a(1,1:4),a(2,1:4),'*')
hold on
plot(a(1,5),a(2,5),'r*')
for ii=1:4
plot([a(1,ii),a(1,5)],[a(2,ii),a(2,5)],'r')
end