Compilare: main.cpp: In function 'int main()': main.cpp:29:9: warning: unused variable 'counter' [-Wunused-variable] int n, counter; ^~~~~~~ main.cpp:30:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.in", "r", stdin); ^ main.cpp:31:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.out", "w", stdout); ^ main.cpp:32:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^