Compilare: user.cpp: In function ‘int main()’: user.cpp:31:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &n, &p); ^ user.cpp:36:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &x, &y);//fin >> x >> y; ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from user.cpp:4: In function ‘void* memset(void*, int, size_t)’, inlined from ‘int main()’ at user.cpp:55:21: /usr/include/i386-linux-gnu/bits/string3.h:82:32: warning: call to ‘__warn_memset_zero_len’ declared with attribute warning: memset used with constant zero length parameter; this could be due to transposed parameters [enabled by default] __warn_memset_zero_len (); ^ In function ‘void* memset(void*, int, size_t)’, inlined from ‘int main()’ at user.cpp:56:27: /usr/include/i386-linux-gnu/bits/string3.h:82:32: warning: call to ‘__warn_memset_zero_len’ declared with attribute warning: memset used with constant zero length parameter; this could be due to transposed parameters [enabled by default] __warn_memset_zero_len (); ^ In function ‘void* memset(void*, int, size_t)’, inlined from ‘int main()’ at user.cpp:57:24: /usr/include/i386-linux-gnu/bits/string3.h:82:32: warning: call to ‘__warn_memset_zero_len’ declared with attribute warning: memset used with constant zero length parameter; this could be due to transposed parameters [enabled by default] __warn_memset_zero_len (); ^ /tmp/ccyFxRWi.o: In function `main': user.cpp:(.text.startup+0x16b): warning: memset used with constant zero length parameter; this could be due to transposed parameters