Compilare: user.cpp: In function ‘int main()’: user.cpp:33:26: warning: operation on ‘i’ may be undefined [-Wsequence-point] v[++i]=v[i-1]+a[x]; ^ user.cpp:46:15: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[j+1]=NULL; ^ user.cpp:48:17: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[j]=NULL; ^ user.cpp: In function ‘void fix()’: user.cpp:8:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("1000001.in","r",stdin); ^ user.cpp:9:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("1000001.out","w",stdout); ^ user.cpp: In function ‘int main()’: user.cpp:15:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]); ^ user.cpp:16:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.cpp:18:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&c); ^ user.cpp:27:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&c); ^ user.cpp:36:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&c); ^ user.cpp:39:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&w); ^