My apologies, but while this question is perfectly adequate I will deal with the follow-up question first as it seems a bit...out there.

It must be stressed that military arms throughout history - especially in the Cold War era - did not JUST have a purpose of firepower; it had an enormous diplomatic purpose. When America had the bomb, it was viewed as the world's superpower, but they never intended to actually use it, especially after the destruction that Japan saw when the bombs were dropped. So 'nuking' the USSR for 'military advantage' is not only crude, immoral but would also be a PR disaster. Noone in the world would condone such an act. So? What else would a giant bomb be used for? Of course: diplomacy. The bomb could be used to bully - not by force - by being used as a bargaining chip so that the Americans could get what they wanted from its enemies. An example of this would the the Soviet missiles in Cuba in 1962 - they were removed once the conditions were met that the US removed the bombs they placed in USSR's back door - Turkey. These weapons, as the Cold War progressed, became tools of diplomacy.

In terms of your first question, I would say yes and no. The wartime conferences such as Tehran, Yalta and Potsdam did not at the time determine whether a Cold War was anticipated or not. Hitler was seen as a common enemy and everything revolved around the reconstruction of Europe. Nobody could possibly envision the long, tense Cold War that was to last the remainder of the 20th Century. To me, I would consider that the Cold War surfaced out of a cumulation of actions and responses - whether ideologically or realpolitik is for you to decide - and of course foreign policy changed during this time. Pinning the origin of the Cold War is entirely subjective. With hindsight, the signs were there. But did anyone anticipate the Cold War at the time? Sure. Alexis de Tocqueville foresaw Russia and America being at each other's throats long before it happened. Churchill's Iron Curtain speech. Truman's Iron Fist. But at the scale that actually happened? I doubt it.

SOURCE

Postwar by Tony Judt is an excellent book if you wish to familiarize yourself with the basics.