Compilare: user.cpp: In function ‘int main()’: user.cpp:60:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k,a,b; ^ user.cpp:60:13: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k,a,b; ^ user.cpp:58:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ user.cpp:61:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&N,&M); ^ user.cpp:65:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^