+// ------------------------------- median -------------------------------------
+
+float medianf(float*a, int n)
+{
+ int i,j,l,m;
+ float x;
+ int k=n&1?n/2:n/2-1;
+ l=0;
+ m=n-1;
+ while(l<m) {
+ x=a[k];
+ i=l;j=m;
+ do {
+ while(a[i]<x) i++;
+ while(x<a[j]) j--;
+ if(i<=j) {
+ //swap
+ float t = a[i];
+ a[i] = a[j];
+ a[j] = t;
+ i++;
+ j--;
+ }
+ } while(i<=j);
+ if(j<k) l=i;
+ if(k<i) m=j;
+ }
+ return a[k];
+}
+