Compilare: main.cpp: In function 'int main()': main.cpp:17:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dirichlet.in", "r", stdin); ^ main.cpp:18:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dirichlet.out", "w", stdout); ^ main.cpp:20:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:6:20: warning: 'p2' may be used uninitialized in this function [-Wmaybe-uninitialized] long long aa = a, p; ^ main.cpp:19:22: note: 'p2' was declared here int n, i, p, p1, p2, cat; ^~ main.cpp:6:20: warning: 'p1' may be used uninitialized in this function [-Wmaybe-uninitialized] long long aa = a, p; ^ main.cpp:19:18: note: 'p1' was declared here int n, i, p, p1, p2, cat; ^~