Compilare: user.cpp: In function ‘int main()’: user.cpp:100:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[top].size();++i){ ^ user.cpp:64:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ninjago.in","r",stdin); ^ user.cpp:65:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ninjago.out","w",stdout); ^ user.cpp:68:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d\n",&T,&N,&M); ^ user.cpp:70:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&x,&y); ^ user.cpp:73:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&c); ^