Compilare: main.cpp: In function 'int idx(char)': main.cpp:21:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:32:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strdup.in","r",stdin); ^ main.cpp:33:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strdup.out","w",stdout); ^