Compilare: main.cpp: In function 'int main()': main.cpp:71:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pirati.in","r",stdin); ^ main.cpp:72:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pirati.out","w",stdout); ^ main.cpp:73:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d\n",&N,&M,&QQ); ^ main.cpp:74:47: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=N;++i) fgets(a[i]+1,Nmax,stdin); ^ main.cpp:96:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&x1,&y1,&x2,&y2); ^