Urgent help needed in matlab ! Thanx

clc; clear all; close all;

q_charge=2e-5;

e_0=8.854*10^-12;

% create grid

x=-10:1:10;

y=-10:1:10;

[X,Y]=meshgrid(x,y);

%%% E field from a single charge

% E field magnitude on the grid

R='something';

E=q_charge./(e_0.*4*pi.*R.^2);

% Voltage magnitude on the grid

% write unit vector for the E field value

%add E field values

% plot the field lines.

figure

contour(X,Y,V_value);

hold on;

quiver(X,Y,i_value,j_value);

axis square;

%%% E field from a Dipole

% E field magnitude on the grid

% Voltage magnitude on the grid

% E field from 1st charge

% E field from 2nd charge

% add E fields

% add Voltages

figure

contour(X,Y,V_total);

hold on;

quiver(X,Y,i3,j3);

axis square;