# include # include # include using namespace std;void main(int argc, char *argv)FILE *fp_ciper, *fp_plain; /密文与明文的文件指针char ch_ciper, ch_plain;int i, temp = 0; /i 用来存储最多次数出现的下标/temp 用在求最多次数时用int key;int j;int num26; /保存密文中字母出现次数for (i = 0; i temp)i = j; /求出最大次数的下标temp = numi;if (j E)ch_plain = (ch_ciper - A - key) % 26) + A); / 解密else ch_plain = (ch_ciper - A - key + 26) % 26) + A);ch_plain = tolower(ch_plain); /把大写明文转换为小写fputc(ch_plain, fp_plain); /把明文卸载文件 plain 中fclose(fp_ciper);fclose(fp_plain);cout “解密成功 !密钥 KEY=“ key “明文已保存在文件中，谢谢使用“ endl;
