indrajee_bariar,u r wrong.

it is not necessary that electric field at every point on a gaussian surface should be same.the only required condition for a gaussian surface is that the surface should be closed.

if the electric field at every point on a gaussian surface is same,then why do we take closed integral of E.dS.

if E is same ,then E should come out of integral sign in the basic gauss's theorem equation itself.( {INT(E.dS)}=q/e0 should become {E.[INT(dS)]=q/e0}

it only comes out of integral sign in special cases like cylinder,sphere etc where field is uniform.

*e0=epsilon zero.