pistonread<-function(refno)
{data<-read.table("http://www.mas.ncl.ac.uk/~nmf16/teaching/mas8303/pistondata.txt")
 out<-cbind(data[,1],data[,2],data[,refno])
 write.table(format(out),row.names=FALSE,col.names=FALSE,quote=FALSE,file="mypistondata.txt")
 }