设串 S1 = '1234567' S2 = 'abab' S3 = 'AAA' S4 = '+-*/@#' 则执行replace(S1 substr(S1 4

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设串 S1 = "1234567" ,S2 = "abab" ,S3 = "AAA" ,S4 = "+-*/@#" ,则执行replace(S1,substr(S1,4,length(S3)),concat(S3,substr(S4,length(S2),index(S2, "a")))) 的结果串是()。

A."1234AAA@"

B."123AAA/7"

C."123AAA7"

D."123AAA/@#7"

设串 S1 = '1234567'  S2 = 'abab'  S3 = 'AAA'  S4 = '+-*/@#'  则执行replace(S1 substr(S1 4

热搜:已知矩阵A的伴随矩阵A*=diag(1,1,1,8,)且ABA-1=BA-1 3