Compilare: main.cpp: In function 'char next_char()': main.cpp:11:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,val,stdin); ^ main.cpp: In function 'int query(int, int, int, int)': main.cpp:124:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:127:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("obstacole.in","r",stdin); ^ main.cpp:128:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("obstacole.out","w",stdout); ^