Compilare: main.cpp: In function 'void build()': main.cpp:58:14: warning: unused variable 'ok' [-Wunused-variable] bool ok = 0; ^~ main.cpp: In function 'int main()': main.cpp:126:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("unicat.in", "r", stdin); ^ main.cpp:127:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("unicat.out", "w", stdout); ^ main.cpp:133:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s + 1); ^ main.cpp:137:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s + 1); ^