C+实现单表密码加解密

C+实现单表密码输入输出输入：加密密钥：hellomingwen.txt的内容：Itisanicedream,dearpapaIseeyouinmydreamwithsmilefacebutyouhadnoanywords,Imissyouverymuch.输出：密文.txt的内容：Itfshmflaorahk,oahrphphIsaaynufmkyorahkwftdskfjabhlaeutynudhomnhmywnros,Ikfssynuvarykuld.