Main.cc: In function ‘int main()’: Main.cc:10:11: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(str); ^ In file included from /usr/include/stdio.h:862:0, from /usr/include/c++/7/cstdio:42, from Main.cc:1: /usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here gets (char *__str) ^~~~ Main.cc:11:3: error: ‘strlwr’ was not declared in this scope strlwr(str);//全部转成小写字母 ^~~~~~ Main.cc:11:3: note: suggested alternative: ‘strstr’ strlwr(str);//全部转成小写字母 ^~~~~~ strstr Main.cc:10:7: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ~~~~^~~~~