Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:15:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(s); i++) ^ user.cpp:17:24: error: ‘isalnum’ was not declared in this scope if(isalnum(s[i])) ^ user.cpp:29:32: error: ‘islower’ was not declared in this scope if(islower(aux[k-1])) ^ user.cpp:47:32: error: ‘islower’ was not declared in this scope if(islower(aux[k-1])) ^ user.cpp:10:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.in","r",stdin); ^ user.cpp:11:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.out","w",stdout); ^ user.cpp:12:24: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,1061,stdin); ^