Compilare: user.cpp: In function ‘int main()’: user.cpp:16:66: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(!stiva.empty() && stiva.top()<x[i] && stiva.size()+n-i>=m) ^ user.cpp:18:73: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!stiva.empty() && stiva.top()<x[i] && stiva.size()+n-i>=m) ^ user.cpp:25:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(stiva.empty() || stiva.size()<m) ^ user.cpp:8:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.in","r",stdin); ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.out","w",stdout); ^ user.cpp:11:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&n,&m); ^ user.cpp:12:11: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(x+1); ^ /tmp/cc92cfq4.o: In function `main': user.cpp:(.text.startup+0x72): warning: the `gets' function is dangerous and should not be used.