Compilare: user.cpp: In function ‘int main()’: user.cpp:22:23: warning: unused variable ‘l’ [-Wunused-variable] int n,m,a,b,i,j,k,l,temp; ^ user.cpp:22:25: warning: unused variable ‘temp’ [-Wunused-variable] int n,m,a,b,i,j,k,l,temp; ^ user.cpp:20:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ndap.in","r",stdin); ^ user.cpp:21:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ndap.out","w",stdout); ^ user.cpp:23:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:25:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^