Compilare: user.cpp: In function ‘int main()’: user.cpp:117:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spiridusi.in","r",stdin); ^ user.cpp:118:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spiridusi.out","w",stdout); ^ user.cpp:120:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&c); ^ user.cpp:123:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&w[i]); ^ user.cpp:126:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&f[i]); ^ user.cpp:130:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp: In function ‘void dfs(int)’: user.cpp:55:43: warning: ‘sol1’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(a<=mid) Query(2*nod,st,mid,a,b); ^ user.cpp:63:13: note: ‘sol1’ was declared here int l,r,sol1; ^