During Apartheid in South Africa people were classified as black, white or coloured. However, in reality it was along the white and the rest line that segregation happened. I think this is why most people make the black and white divide when in reality it was white against anyone that was not white. Hope this answer helps.
It's hard to say. We tend to think of segregation on a black-white divide. But I think it's more complicated than that. I could be wrong, but at the moment I think segregation was not purely between whites and blacks. I think, being that Italians, Germans and Spanish were also discriminated against, it was also applied to them.
No it wasn't. That's why they had colored signs (anything other than white) instead of just black and white signs. If you weren't white then you couldn't be with the whites. All races were segregated. They all were in different communities and schools. Whatever race you were you had to be with or it wasn't socially accepted.
Segregation wasn't just applied to blacks in the 1940s through 1960s. Signs by water fountains didn't just say "blacks" or "negroes." They said "colored." People who didn't have white skin included Native Americans and Hispanics. They, too, were discriminated against although the predominant ethnicity affected at the time were blacks. The term "colored" included everyone. Keep in mind, Japanese-Americans were discriminated against during World War II when they were sent to "internment camps" after Pearl Harbor. Everyone who wasn't white was treated as a second-class citizen until the 1970s.