How to restart network-manager without root password

Question

My wireless is flaky so I'd like to be able to restart network-manager with a script WITHOUT having to type the root password.

I tried making a c program that does this:

setuid(0);
system("service network-manager restart");

And I set the permissions as follows:

sudo chown root:root suscript
sudo chmod 4755 suscript

But when I run it, I get this error:

stop: Unknown job: network-manager
start: Unknown job: network-manager

I guess something is wrong in the environment, but I don't know what. Can anyone help? Thanks.

By the way, this is xubuntu 14.04.