Compilare: user.cpp: In function ‘int main()’: user.cpp:19:13: warning: variable ‘ok’ set but not used [-Wunused-but-set-variable] int n,i,ok,j,a,b,last,x,y; ^ user.cpp:19:16: warning: unused variable ‘j’ [-Wunused-variable] int n,i,ok,j,a,b,last,x,y; ^ user.cpp:19:22: warning: unused variable ‘last’ [-Wunused-variable] int n,i,ok,j,a,b,last,x,y; ^ user.cpp:19:27: warning: unused variable ‘x’ [-Wunused-variable] int n,i,ok,j,a,b,last,x,y; ^ user.cpp:19:29: warning: unused variable ‘y’ [-Wunused-variable] int n,i,ok,j,a,b,last,x,y; ^ user.cpp:17:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dunarea.in","r",stdin); ^ user.cpp:18:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dunarea.out","w",stdout); ^ user.cpp:20:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&n); ^ user.cpp:22:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&v[i].st,&v[i].dr); ^