Compilare: main.cpp: In function 'int main()': main.cpp:11:21: warning: unused variable 'k' [-Wunused-variable] int n , i , j , k; ^ main.cpp:9:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sir23.in" , "r" , stdin); ^ main.cpp:10:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sir23.out" , "w" , stdout); ^ main.cpp:12:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^