Compilare: user.cpp: In function ‘int main()’: user.cpp:131:9: warning: unused variable ‘p’ [-Wunused-variable] int p = n; ^ user.cpp:132:9: warning: unused variable ‘already’ [-Wunused-variable] int already = 0; ^ user.cpp:133:9: warning: unused variable ‘r’ [-Wunused-variable] int r = n; ^ user.cpp:72:25: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(s,1,6000000,f); ^