Compilare: main.cpp: In function 'int main()': main.cpp:88:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fibo4.in" , "r" ,stdin) ; ^ main.cpp:89:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fibo4.out" ,"w" , stdout) ; ^ main.cpp:90:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("in.in" , "r" ,stdin) ; ^