error in matlab code for mean and standard deviation

[Shruti01]

Hello all,
I have written following matlab code for calculating the mean and standard deviation of x but I am getting an error for mean and standard deviation as NaN (Not a number). Kindly help. What is wrong with my code.

clc;
  close all;
  clear all;
  x =  [4.2426 + 3.1659i
     2.2956 + 2.3891i
    -2.2271 + 4.5607i
    -1.9326 - 3.1940i
     3.6840 + 3.0343i
     0.0677 + 2.9262i
    -2.9779 - 1.4531i
    -2.4633 + 3.2697i
    -3.9887 + 0.4685i
    -2.9322 - 2.2252i
    -4.3754 - 2.6187i
    -3.4865 - 3.4461i];
  sum_x = 0; 
  sum_x2 = 0;
  n=0;
      while x>=0
          n=n+1;
          sum_x=sum_x+x;
          sum_x2=sum_x2+x^2;
      end
      x_bar=sum_x/n;
      std_dev=sqrt((n*sum_x2-sum_x^2)/(n*(n-1)));

 

[andre_luis]

I noticed on above code at while statement that you perform evaluation of an imaginary array number on its argument. I presume it is expected an scalar one.