[R] Graph with values of coordinates of points in x axis

[Massimiliano Tripoli]

Hi all,

I want to draw a line with the values of x marked in X axis.

I tried with
x <- c(0,6,12,18,24,30)  #coordinates of points x
y <- c(2,5,7,5,7,16)     #coordinates of points y
plot(x,type="n",xlab="Months",ylab="Y 
values",main="main",ylim=c(0,16),xlim=c(0,30))
lines(x,y)

The graph shows by default an increment of the sequence in x axis that I'm 
not able to change.
I'would like to have 0,6,12,18,24,30 and not 0,10,15,20,25,30.
Any hint is appreciated.

Thanks in advance.