Compilare: user.cpp: In function ‘int main()’: user.cpp:56:11: warning: unused variable ‘f’ [-Wunused-variable] FILE *f = fopen("disjoint.in", "r"); ^ user.cpp:57:11: warning: unused variable ‘g’ [-Wunused-variable] FILE *g = fopen("disjoint.out","w"); ^ user.cpp:58:34: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,buff_size,1,stdin); ^ user.cpp: In function ‘void read(int&)’: user.cpp:10:111: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] while(buff[pos] < '0' || buff[pos] > '9') if(++pos == buff_size) fread(buff, buff_size,1, stdin), pos = 0; ^ user.cpp:15:73: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos == buff_size) fread(buff, 1, buff_size, stdin), pos = 0; ^