Compilare: user.cpp:12:0: warning: "buff_size" redefined [enabled by default] #define buff_size 666666 ^ user.cpp:5:0: note: this is the location of the previous definition #define buff_size 250010 ^ user.cpp: In function ‘int main()’: user.cpp:72:36: 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, buff_size, stdin); ^ user.cpp: In function ‘void read(int&)’: user.cpp:18:111: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] while(buff[pos] < '0' || buff[pos] > '9') if(++pos == buff_size) fread(buff, 1,buff_size, stdin), pos = 0; ^ user.cpp:23:73: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos == buff_size) fread(buff, 1, buff_size, stdin), pos = 0; ^