Subj : Re: Why not unions To : comp.programming From : Flavius Vespasianus Date : Tue Jul 26 2005 11:18 pm "Shwetabh" wrote in news:1122405363.654011.210940 @f14g2000cwb.googlegroups.com: > Hi, my question is related with data structures. > Why are only structures used for implementing data structures. > Why not unions when they are more memory efficient than structures. The only place where Unions theoretically are useful is to get multiple views of the same physical data. In other words to have a variable format record structure (e.g. pascal variant record). The problem is with all the alignment and data type differences among compilers, this is effectively useless these days. I think you are mistaken about unions being more memory efficient than structures. .