Welllll, that's also complicated
Communism in it's pure form has, to the best of my knowledge, never been tried outside of a small commune. In pure communism, as far as I understand, there's no money, and people are just supposed to take what they need and put their work in. I don't know how if totalitarianism is a necessary part of the doctrine. Obviously, people are greedy, so this system couldn't exist without strict government controls on who gets what, or unless people became devoid of all evil.
Socialism is actually what the Soviet Union was (Union of Soviet SOCIALIST Republics), and it involves government control of everything, and regulation of the economy and all, but there's still money, and people still sort of have private property (in the sense that people can buy things and own them instead of it being owned by the collective, but the government can of course take what they want in the end, so ownership can be kinda shaky).
I would still call the Soviets communists though, because that's what the actual party in control was, and I believe it was Lenin that said "Communism is the goal of socialism" or something. The Soviet Union used communist ideology (such as communism will spread to every part of the world), but their economic system was socialist. Nazi Germany used Nazi ideology, but their economic system was also socialist. And since Nazism really REALLY hates communism (they saw it and capitalism as Jewish plots to take over the world) they wanted to go kill communism, even though, in essence, it was the same economic system.
So..... there ya have it