Compilare: user.cpp: In function ‘void init()’: user.cpp:22:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d %d",&n,&m,&k); ^ user.cpp:24:45: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i=1;i<=k;i++) { fscanf(f,"%d",&nr); ^ user.cpp:30:56: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d %d",&n1,&n2,&val); ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from user.cpp:3: In function ‘void* memset(void*, int, size_t)’, inlined from ‘void init()’ at user.cpp:17:24: /usr/include/i386-linux-gnu/bits/string3.h:85:70: warning: call to void* __builtin___memset_chk(void*, int, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^ In function ‘void* memset(void*, int, size_t)’, inlined from ‘void init()’ at user.cpp:18:22: /usr/include/i386-linux-gnu/bits/string3.h:85:70: warning: call to void* __builtin___memset_chk(void*, int, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^