r - Barplot with deviations from a non zero number -

i have measurements of variable. values positive. in barchart want show measurements , deviation of measurements overall mean. bars go mean , go down. in order such graph tried using offset barplot function not work. found solution not ideal , prone mistakes. applying axes requires tweaking of numbers. there more elegant solution this? thanks!

(aaa    <-  c(1: 10)) (meanz  <-  mean(aaa))  (ccc    <-  aaa-meanz[1])  barplot(ccc, axes=false, ylim=c(-5, 5)) (yvals      <-  c(-5, 0, 5)) (yvalscorr  <-  yvals+meanz) axis(side=2, at=yvals, labels=yvalscorr,    mgp=c(1,1,1),   outer=true, lwd=2, las=1, cex.axis=1.0,   tck=0.02, hadj=0.5,  padj=0.5, pos=-0.2) 

this more or less intend (though more flexibility setting axes values @ 0 needed)

what defining function this

x <- cumsum(runif(10)) 0 <- mean(x)  offsetbarplot <- function(x, zero=0, ..., yaxt="c", ylim) {     xo <- x-zero     yax <- pretty(x)     if (missing(ylim))          ylim<-range(yax-zero)     else         ylim<-ylim-zero     barplot(xo, ..., yaxt=ifelse(yaxt=="c","n",yaxt), ylim=ylim)     if(yaxt=="c") {         axis(side=2, at=yax-zero, labels=yax)     } }  offsetbarplot(x, zero) 

this way can use of barplot code possible. can still pass many of same options. draw custom axis on side.