cointoss <- function(tosses, trials)
  {
    p=.5;
    x = rbinom(trials, tosses, p);
    xvals=0:tosses;
    breaks=seq(-1,tosses) + 1/2;
    ylim<-range(0,1.5*dbinom(xvals, tosses, p));
    hist(x, probability=T, breaks=breaks, ylim=ylim,
         main=sprintf("Histogram of %i Coin Tosses, %i Times", tosses, trials));
    points(xvals, dbinom(xvals, tosses, p), type="p", lwd=3);
    points(xvals, dbinom(xvals, tosses, p), type="h", lwd=3);
  }