Compilare: user.cpp: In function ‘int main()’: user.cpp:113:10: warning: unused variable ‘a’ [-Wunused-variable] char a,flag; ^ user.cpp: In function ‘char nextch()’: user.cpp:42:29: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,1,MAXBUF,fi); ^