Compilare: user.cpp: In function ‘int main()’: user.cpp:67:21: warning: unused variable ‘cnt’ [-Wunused-variable] int n,i, j,mx=0,cnt, id, jd; ^ user.cpp: In function ‘void read(int&)’: user.cpp:16:96: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] while(!isdigit(buff[pos])) if(++pos == buff_size) fread(buff, 1,buff_size, stdin), pos = 0; ^ user.cpp:21:73: 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; ^ user.cpp: In function ‘int main()’: user.cpp:67:30: warning: ‘jd’ may be used uninitialized in this function [-Wmaybe-uninitialized] int n,i, j,mx=0,cnt, id, jd; ^ user.cpp:67:26: warning: ‘id’ may be used uninitialized in this function [-Wmaybe-uninitialized] int n,i, j,mx=0,cnt, id, jd; ^