一，问题重述
集合中的元素为小字母a小写字母z，实现以下运算：
实现集合表示和集合的运算（并、交、差、补）判断集合之间、元素和集合之间的关系二，源程序及注释i
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cludeioma
iphi
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iohi
cludestdiohi
cludeprocesshi
cludestri
ghi
cludemathhi
cludestdlibh
chara100b100c100i
tpqij
chard26t
voidi
itcharavoiddisplaycharavoidjiaocharacharbcharcvoidbi
gcharacharbcharcvoidchacharacharbcharcvoidbucharavoidjihejihecharacharbvoidyua
sujihechara
voidmai
charchoice
while1

system