Compilare: user.cpp: In function ‘int main()’: user.cpp:34:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = i-1;j >= 1 && p[i].first - p[j].first <= dmn;j--){ ^ user.cpp:23:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in", "r", stdin); ^ user.cpp:24:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.out", "w", stdout); ^ user.cpp:25:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:27:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^