Compilare: user.cpp: In function ‘int main()’: user.cpp:29:11: warning: statement has no effect [-Wunused-value] for(in;fi!=in;in++) ^ user.cpp:44:15: warning: statement has no effect [-Wunused-value] for(in;fi!=in;in++) ^ user.cpp:10:19: warning: variable ‘c’ set but not used [-Wunused-but-set-variable] int n,m,x,y,a,b,i,c,z,k=0; ^ user.cpp:10:21: warning: unused variable ‘z’ [-Wunused-variable] int n,m,x,y,a,b,i,c,z,k=0; ^ user.cpp:8:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen("graf.in","r",stdin); ^ user.cpp:9:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out","w",stdout); ^ user.cpp:14:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&x,&y); ^ user.cpp:17:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^